CA3042920C

CA3042920C - Partial upgrading of bitumen with subsurface solvent deasphalting and at-surface thermal treatment

Info

Publication number: CA3042920C
Application number: CA3042920A
Authority: CA
Inventors: Iftikhar Huq; Prabhakar Reddy; Randy Segato; Paul Morris; Govinder Parmar
Original assignee: Suncor Energy Inc
Current assignee: Suncor Energy Inc
Priority date: 2019-05-10
Filing date: 2019-05-10
Publication date: 2021-11-09
Anticipated expiration: 2039-05-10
Also published as: CA3042920A1

Abstract

Partial upgrading techniques that include subsurface deasphalting and mild thermal treatment at surface to produce a partially upgraded bitumen product are provided. The processes can include introducing an asphaltene-precipitating solvent into a subsurface formation to contact bitumen that includes a light fraction and a heavy fraction comprising asphaltenes, inducing in situ precipitation of at least a portion of the asphaltenes within the subsurface formation to produce a precipitated asphaltene material and a mobilized fluid comprising a deasphalted bitumen fraction, recovering the mobilized fluid as a production fluid comprising the deasphalted bitumen fraction, water, solids and a portion of the asphaltene-precipitating solvent while leaving a majority of the precipitated asphaltene material within the subsurface formation, separating deasphalted bitumen from the production fluid, and subjecting the deasphalted bitumen to a thermal treatment at about or below incipient coking conditions to produce the partially upgraded bitumen product.

Description

PARTIAL UPGRADING OF BITUMEN WITH SUBSURFACE SOLVENT
DEASPHALTING AND AT-SURFACE THERMAL TREATMENT
TECHNICAL FIELD
[1] The technical field generally relates to the treatment of bitumen, and more particularly to the partial upgrading of bitumen using subsurface solvent deasphalting followed by at-surface thermal treatment.
BACKGROUND

[2] Bitumen generally has a high viscosity, which can make pipeline transportation and processing of bitumen difficult. Various methods exist to upgrade bitumen and increase its suitability for pipeline transportation, although such methods have various drawbacks.

[3] For instance, bitumen upgrader facilities of various designs can upgrade the bitumen to produce a bitumen product having desirable physicochemical characteristics for pipelinability. However, conventional upgrader facilities have high associated capital and operating costs. In addition, at-surface deasphalting processes necessitate the handling and treatment of precipitated asphaltenes and can also lead to lower yields, which can result in higher operating costs and reduced revenue. Furthermore, in some conventional upgrading methods, such as severe thermal cracking, hydrogen originally present in the bitumen is lost to the gas phase such that, in the absence of added hydrogen, significant and undesirable olefin production can occur. In order to meet pipeline specifications, the olefin content of the bitumen should be minimized, typically to less than 1 wt% (1-decene equivalent). Thus, upgrading methods that produce bitumen products having a high olefin content typically use an external source of hydrogen, via some form of hydroprocessing.
The hydroprocessing can facilitate compensating for at least some of the bitumen hydrogen losses that occurred during cracking, saturating or converting the olefins by breaking down the carbon-to-carbon double bonds and converting them to single bonds, and stabilizing cracked products to achieve targeted bitumen quality requirements.
Hydroprocessing can include the addition of hydrogen in a separate unit, for example.
However, for economic and technical reasons, various traditional hydroprocessing methods are generally avoided since external hydrogen production has high associated costs. Indeed, any approach using external hydrogen is likely to have higher capital and operating costs.

[4] Another option to improve bitumen viscosity is to dilute the bitumen, for example with naphtha or natural gas condensate as a diluent. This diluted bitumen is often referred to as "dilbit". While bitumen dilution does not have the same capital cost penalty as a bitumen upgrader facility, it still can have high associated operating costs. For example, since dilbit includes a significant volume of diluent (e.g., one third diluent and two thirds bitumen per barrel of diluted bitumen), significant pipeline capacity is therefore taken up by the diluent for pipelining of the dilbit as well as the return pipelining of separated diluent to be reused in bitumen dilution. Thus, since diluent often travels to and from the bitumen recovery operation, approximately a third of the pipeline capacity can be required for diluent transport and approximately a third of the hydrocarbon inventory can be diluent, which is costly and inefficient.

[5] Other bitumen upgrading methods can involve high severity operating conditions, significant coking, and/or hydrocracking, which can also involve technical challenges as well as high capital and operating costs.

[6] Various challenges exist in terms of technologies for bitumen upgrading and viscosity reduction.
SUMMARY

[7] In accordance with a first aspect, there is provided a process for producing a partially upgraded bitumen product. The process comprises an in situ bitumen recovery operation comprising: introducing an asphaltene-precipitating solvent into a subsurface formation to contact bitumen contained in the subsurface formation, the bitumen comprising a light fraction and a heavy fraction comprising asphaltenes; inducing in situ precipitation of at least a portion of the asphaltenes within the subsurface formation to produce a precipitated asphaltene material and a mobilized fluid comprising a deasphalted bitumen fraction;
recovering the mobilized fluid as a production fluid comprising the deasphalted bitumen fraction, water, solids and a portion of the asphaltene-precipitating solvent while leaving a majority of the precipitated asphaltene material within the subsurface formation;
separating deasphalted bitumen from the production fluid; determining a property of the deasphalted bitumen; and subjecting the deasphalted bitumen to a thermal treatment at about or below incipient coking conditions to produce the partially upgraded bitumen product, wherein the thermal treatment comprises adjusting an operating parameter of the thermal treatment based on the property of the deasphalted bitumen stream.

[8] According to a possible implementation, all of the precipitated asphaltene material is left within the subsurface formation and the production fluid contains substantially none of the precipitated asphaltene material.

[9] According to a possible implementation, introducing the asphaltene-precipitating solvent into the subsurface formation comprises injecting the asphaltene-precipitating solvent via a horizontal injection well provided in the subsurface formation;
and wherein the production fluid is recovered via a horizontal production well that is located below the horizontal injection well.

[10] According to a possible implementation, the asphaltene-precipitating solvent comprises an alkane solvent.

[11] According to a possible implementation, the alkane solvent comprises propane, butane, pentane, hexane, heptane or a mixture thereof.

[12] According to a possible implementation, the alkane solvent comprises propane.

[13] According to a possible implementation, the alkane solvent comprises butane.

[14] According to a possible implementation, the alkane solvent comprises pentane.

[15] According to a possible implementation, subjecting the deasphalted bitumen to the thermal treatment comprises heating the deasphalted bitumen to a temperature between 200 C and 475 C.

[16] According to a possible implementation, subjecting the deasphalted bitumen to the thermal treatment comprises heating the deasphalted bitumen to a temperature between 350 C and 450 C.

[17] According to a possible implementation, the thermal treatment is performed for a duration of up to 300 minutes.

[18] According to a possible implementation, the thermal treatment is performed for a duration of between 15 minutes and 240 minutes.

[19] According to a possible implementation, the thermal treatment is performed at a pressure between 50 psig and 1500 psig.

[20] According to a possible implementation, the thermal treatment is performed at a pressure between 50 psig and 1000 psig.

[21] According to a possible implementation, separating the deasphalted bitumen from the production fluid comprises removing water and solids from the production fluid.

[22] According to a possible implementation, separating deasphalted bitumen from the production fluid comprises recovering at least a portion of the asphaltene-precipitating solvent from the production fluid to obtain a recovered asphaltene-precipitating solvent for reintroduction into the subsurface formation.

[23] According to a possible implementation, introducing the asphaltene-precipitating solvent into the subsurface formation comprises vaporizing the asphaltene-precipitating solvent and injecting the asphaltene-precipitating solvent into the subsurface formation in vapor phase.

[24] According to a possible implementation, conditions of the in situ bitumen recovery operation comprise providing a solvent-to-bitumen ratio of the mobilized fluid that is sufficiently high to cause the in situ precipitation of asphaltenes at operating extraction temperatures and pressures.

[25] According to a possible implementation, the solvent-to-bitumen ratio of the mobilized fluid is sufficiently high to cause substantially all of the asphaltenes to precipitate such that the deasphalted bitumen fraction is fully deasphalted.

[26] According to a possible implementation, the solvent-to-bitumen ratio of the mobilized fluid is provided to cause partial precipitation of asphaltenes such that the deasphalted bitumen fraction comprises a reduced asphaltene content.

[27] According to a possible implementation, the property of the deasphalted bitumen comprises at least one of asphaltene content of the deasphalted bitumen, a compositional characteristic of the deasphalted bitumen, a viscosity of the deasphalted bitumen and a density of the deasphalted bitumen.

[28] According to a possible implementation, the process further comprises combining the deasphalted bitumen with a second hydrocarbon material to obtain a combined deasphalted bitumen material that is subjected to the thermal treatment.

[29] According to a possible implementation, combining the deasphalted bitumen with the second hydrocarbon material to obtain the combined deasphalted bitumen material is performed when the property of the deasphalted bitumen is above or below a given threshold.

[30] According to a possible implementation, the second hydrocarbon material comprises a second deasphalted bitumen.

[31] According to a possible implementation, the second deasphalted bitumen is obtained from a second subsurface formation.

[32] According to a possible implementation, the process further comprises subjecting the deasphalted bitumen to an at-surface deasphalting treatment to further reduce the asphaltene content of the deasphalted bitumen prior to the thermal treatment.

[33] According to a possible implementation, the at-surface deasphalting treatment comprises using at least a portion of the recovered asphaltene-precipitating solvent as deasphalting solvent.

[34] According to a possible implementation, the deasphalted bitumen and the second hydrocarbon material are combined in relative proportions so that the combined deasphalted bitumen material has a predetermined composition based on desired operating parameters of the thermal treatment.

[35] According to a possible implementation, the process further comprises combining multiple production fluids respectively obtained from a plurality of in situ recovery wells to form a combined production fluid, and separating the deasphalted bitumen from the combined production fluid.

[36] According to a possible implementation, subjecting the deasphalted bitumen to the thermal treatment comprises maintaining the deasphalted bitumen in liquid phase during the thermal treatment.

[37] According to a possible implementation, maintaining the deasphalted bitumen in liquid phase comprises providing conditions to cause a transfer of hydrogen from the heavy fraction to the light fraction directly in the liquid phase.

[38] According to a possible implementation, the thermal treatment comprises supplying the deasphalted bitumen to a thermal treatment vessel and withdrawing the partially upgraded bitumen product from the thermal treatment vessel as a single stream from a product outlet.

[39] According to a possible implementation, the thermal treatment comprises feeding the single stream of partially upgraded bitumen product to a gas separator and removing at least a portion of a gas phase from the partially upgraded bitumen product.

[40] According to a possible implementation, adjusting the operating parameter of the thermal treatment in accordance with the property of the deasphalted bitumen comprises adjusting at least one of temperature, duration and pressure of the thermal treatment.

[41] According to a possible implementation, subjecting the deasphalted bitumen to the thermal treatment comprises adding an external source of hydrogen to the deasphalted bitumen.

[42] According to a possible implementation, subjecting the deasphalted bitumen to the thermal treatment comprises adding a hydrogen transfer agent to the deasphalted bitumen.

[43] According to a possible implementation, the external source of hydrogen is a diatomic hydrogen-containing gas.

[44] According to a possible implementation, the hydrogen transfer agent comprises paraffins, naphthenes, naphtheno-aromatics and/or aromatics.

[45] According to a possible implementation, the hydrogen transfer agent comprises at least one of butane, propane, methane, tetralin, decalin, and anthracene.

[46] According to a possible implementation, the hydrogen transfer agent comprises a hydrogen donor.

[47] According to a possible implementation, the hydrogen donor comprises at least one of tetralin, decalin, synthetic crude oil, fractions of synthetic crude oil, tight oil, shale oil and light crude oils.

[48] According to a possible implementation, the process further comprises diluting the partially upgraded bitumen product with a diluent to obtain a diluted bitumen product.

[49] According to a possible implementation, the diluent comprises an aromatic diluent, a naphthenic diluent, natural gas condensates, synthetic crude, a fraction of synthetic crude oil or combinations thereof.

[50] According to a possible implementation, the diluted bitumen product is diluted to a predetermined pipeline specification, and is also based on the determined property of the partially upgraded bitumen product.

[51] According to a possible implementation, the process further comprises recovering heat from the partially upgraded bitumen product and reusing at least a portion of the recovered heat in the in situ bitumen recovery operation.

[52] According to a possible implementation, the heat is at least partly reused for pre-heating a process stream that is part of the in situ bitumen recovery operation prior to a unit operation.

[53] According to a possible implementation, the deasphalted bitumen has a variable composition over time.

[54] According to a possible implementation, the deasphalted bitumen has a higher asphaltene content during an earlier stage of the in situ bitumen recovery operation, and a lower asphaltene content during a later stage of the in situ bitumen recovery operation.

[55] According to a possible implementation, the earlier stage comprises a startup stage, and the later stage comprises a normal operation stage of the in situ bitumen recovery operation.

[56] According to a possible implementation, the process further comprises controlling the in situ bitumen recovery operation or the thermal treatment or a combination thereof, based on the variable composition of the deasphalted bitumen.

[57] According to a possible implementation, the thermal treatment is operated at lower severity conditions when the deasphalted bitumen has a higher asphaltene content, and is operated at higher severity conditions when the deasphalted bitumen has a lower asphaltene content.

[58] According to a possible implementation, the thermal treatment is continuously controlled based on the variable composition of the deasphalted bitumen.

[59] According to a possible implementation, the thermal treatment is intermittently controlled based on the variable composition of the deasphalted bitumen.

[60] In accordance with another aspect, there is provided a process for producing a partially upgraded bitumen product. The process comprises recovering a mobilized subsurface fluid as production fluid comprising a deasphalted bitumen fraction as part of an in situ bitumen recovery operation, comprising: introducing an asphaltene-precipitating solvent into a subsurface formation to contact bitumen contained in the subsurface formation, the bitumen comprising a light fraction and a heavy fraction comprising asphaltenes; inducing in situ precipitation of at least a portion of the asphaltenes within the subsurface formation to produce a precipitated asphaltene material and the mobilized subsurface fluid comprising the deasphalted bitumen fraction; and producing the mobilized subsurface fluid to the surface as the production fluid that includes the deasphalted bitumen fraction, water, solids and a portion of the asphaltene-precipitating solvent while leaving a majority of the precipitated asphaltene material within the subsurface formation;

separating deasphalted bitumen from the production fluid; determining a property of the deasphalted bitumen; adjusting a variable related to the in situ bitumen recovery operation based on the property of the deasphalted bitumen to obtain a deasphalted bitumen feedstock; and subjecting the deasphalted bitumen feedstock to a thermal treatment at about or below incipient coking conditions to produce the partially upgraded bitumen product.

[61] According to a possible implementation, all of the precipitated asphaltene material is left within the subsurface formation and the production fluid contains substantially none of the precipitated asphaltene material.

[62] According to a possible implementation, introducing the asphaltene-precipitating solvent into the subsurface formation comprises injecting the asphaltene-precipitating solvent via a horizontal injection well provided in the subsurface formation;
and wherein the production fluid is recovered via a horizontal production well that is located below the horizontal injection well.

[63] According to a possible implementation, the asphaltene-precipitating solvent comprises an alkane solvent.

[64] According to a possible implementation, the alkane solvent comprises propane, butane, pentane, hexane, heptane or a mixture thereof.

[65] According to a possible implementation, the alkane solvent comprises propane.

[66] According to a possible implementation, the alkane solvent comprises butane.

[67] According to a possible implementation, the alkane solvent comprises pentane.

[68] According to a possible implementation, subjecting the deasphalted bitumen to the thermal treatment comprises heating the deasphalted bitumen to a temperature between 200 C and 475 C.

[69] According to a possible implementation, subjecting the deasphalted bitumen to the thermal treatment comprises heating the deasphalted bitumen to a temperature between 350 C and 450 C.

[70] According to a possible implementation, the thermal treatment is performed for a duration of up to 300 minutes.

[71] According to a possible implementation, the thermal treatment is performed for a duration of between 15 minutes and 240 minutes.

[72] According to a possible implementation, the thermal treatment is performed at a pressure between 50 psig and 1500 psig.

[73] According to a possible implementation, the thermal treatment is performed at a pressure between 50 psig and 1000 psig.

[74] According to a possible implementation, separating deasphalted bitumen from the production fluid comprises removing water and solids from the production fluid.

[75] According to a possible implementation, separating deasphalted bitumen from the production fluid comprises recovering at least a portion of the asphaltene-precipitating solvent from the production fluid to obtain a recovered asphaltene-precipitating solvent for reintroduction into the subsurface formation.

[76] According to a possible implementation, introducing the asphaltene-precipitating solvent into the subsurface formation comprises vaporizing the asphaltene-precipitating solvent at surface, and injecting the asphaltene-precipitating solvent into the subsurface formation in vapor phase.

[77] According to a possible implementation, conditions of the in situ bitumen recovery operation comprise providing a solvent-to-bitumen ratio of the mobilized fluid that is sufficiently high to cause the in situ precipitation of asphaltenes at operating extraction temperatures and pressures.

[78] According to a possible implementation, the solvent-to-bitumen ratio of the mobilized fluid is sufficiently high to cause substantially all of the asphaltenes to precipitate such that the deasphalted bitumen fraction is fully deasphalted.

[79] According to a possible implementation, the solvent-to-bitumen ratio of the mobilized fluid is provided to cause partial precipitation of asphaltenes such that the deasphalted bitumen fraction comprises a reduced asphaltene content.

[80] According to a possible implementation, adjusting the variable related to the in situ bitumen recovery operation comprises adjusting at least one operating parameter related thereto.

[81] According to a possible implementation, adjusting the operating parameter of the in situ bitumen recovery operation comprises at least one of modifying the type or composition of the asphaltene-precipitating solvent introduced into the subsurface formation, modifying an amount or rate of the asphaltene-precipitating solvent introduced into the subsurface formation, adjusting a solvent-to-bitumen ratio within the subsurface formation or of the production fluid, adjusting a temperature of the asphaltene-precipitating solvent to be introduced in the subsurface formation, adjusting a temperature within the subsurface formation, and adjusting heat that is provided to the reservoir.

[82] According to a possible implementation, adjusting the variable related to the in situ bitumen recovery operation comprises adjusting at least one characteristic of the deasphalted bitumen.

[83] According to a possible implementation, the property of the deasphalted bitumen comprises at least one of asphaltene content of the deasphalted bitumen, a compositional characteristic of the deasphalted bitumen, a viscosity of the deasphalted bitumen and a density of the deasphalted bitumen.

[84] According to a possible implementation, the process further comprises combining the deasphalted bitumen with a second hydrocarbon material to obtain a combined deasphalted bitumen material that is subjected to the thermal treatment.

[85] According to a possible implementation, combining the deasphalted bitumen with the second hydrocarbon material to obtain the combined deasphalted bitumen material is performed when the property of the deasphalted bitumen is above or below a given threshold.

[86] According to a possible implementation, the second hydrocarbon material comprises a second deasphalted bitumen.

[87] According to a possible implementation, the second deasphalted bitumen is obtained from a second subsurface formation.

[88] According to a possible implementation, the process further comprises subjecting the deasphalted bitumen to an at-surface deasphalting treatment to further reduce the asphaltene content of the deasphalted bitumen prior to the thermal treatment.

[89] According to a possible implementation, the at-surface deasphalting treatment comprises using at least a portion of the recovered asphaltene-precipitating solvent as deasphalting solvent.

[90] According to a possible implementation, the deasphalted bitumen and the second hydrocarbon material are combined in relative proportions so that the combined deasphalted bitumen material has a predetermined composition based on desired operating parameters of the thermal treatment.

[91] According to a possible implementation, the process further comprises combining multiple production fluids respectively obtained from a plurality of in situ recovery wells to form a combined production fluid, and separating the deasphalted bitumen from the combined production fluid.

[92] According to a possible implementation, subjecting the deasphalted bitumen to the thermal treatment comprises maintaining the deasphalted bitumen in liquid phase during the thermal treatment.

[93] According to a possible implementation, maintaining the deasphalted bitumen in liquid phase comprises providing conditions to cause a transfer of hydrogen from the heavy fraction to the light fraction directly in the liquid phase.

[94] According to a possible implementation, the thermal treatment comprises supplying the deasphalted bitumen to a thermal treatment vessel and withdrawing the partially upgraded bitumen product from the thermal treatment vessel as a single stream from a product outlet.

[95] According to a possible implementation, the thermal treatment comprises feeding the single stream of partially upgraded bitumen product to a gas separator and removing at least a portion of a gas phase from the partially upgraded bitumen product.

[96] According to a possible implementation, subjecting the deasphalted bitumen to the thermal treatment comprises adding an external source of hydrogen to the deasphalted bitumen.

[97] According to a possible implementation, subjecting the deasphalted bitumen to the thermal treatment comprises adding a hydrogen transfer agent to the deasphalted bitumen.

[98] According to a possible implementation, the external source of hydrogen is a diatomic hydrogen-containing gas.

[99] According to a possible implementation, the hydrogen transfer agent comprises paraffins, naphthenes, naphtheno-aromatics and/or aromatics.

[100] According to a possible implementation, the hydrogen transfer agent comprises at least one of butane, propane, methane, tetralin, decalin, and anthracene.

[101] According to a possible implementation, the hydrogen transfer agent comprises a hydrogen donor.

[102] According to a possible implementation, the hydrogen donor comprises at least one of tetralin, decalin, synthetic crude oil, fractions of synthetic crude oil, tight oil, shale oil and light crude oils.

[103] According to a possible implementation, the process further comprises diluting the partially upgraded bitumen product with a diluent to obtain a diluted bitumen product.

[104] According to a possible implementation, the diluent comprises an aromatic diluent, a naphthenic diluent, natural gas condensates, synthetic crude, a fraction of synthetic crude oil or streams thereof.

[105] According to a possible implementation, the diluted bitumen product is diluted to a predetermined pipeline specification.

[106] According to a possible implementation, the process further comprises recovering heat from the partially upgraded bitumen product and reusing at least a portion of the recovered heat in the in situ bitumen recovery operation.

[107] According to a possible implementation, the heat is at least partly reused for pre-heating a process stream that is part of the in situ bitumen recovery operation prior to a unit operation.

[108] According to a possible implementation, the deasphalted bitumen has a variable composition over time.

[109] According to a possible implementation, the deasphalted bitumen has a higher asphaltene content during an earlier stage of the in situ bitumen recovery operation, and a lower asphaltene content during a later stage of the in situ bitumen recovery operation.

[110] According to a possible implementation, the earlier stage comprises a startup stage, and the later stage comprises a normal operation stage of the in situ bitumen recovery operation.

[111] According to a possible implementation, the process further comprises controlling the in situ bitumen recovery operation or the thermal treatment or a combination thereof, based on the variable composition of the deasphalted bitumen.

[112] According to a possible implementation, the thermal treatment is operated at lower severity conditions when the deasphalted bitumen has a higher asphaltene content, and is operated at higher severity conditions when the deasphalted bitumen has a lower asphaltene content.

[113] According to a possible implementation, the thermal treatment is continuously controlled based on the variable composition of the deasphalted bitumen.

[114] According to a possible implementation, the thermal treatment is intermittently controlled based on the variable composition of the deasphalted bitumen.

[115] According to another aspect, there is provided a process for producing a partially upgraded bitumen product. The process comprises an in situ bitumen recovery process comprising: introducing an asphaltene-precipitating solvent into a subsurface formation to contact bitumen contained in the subsurface formation, the bitumen comprising a light fraction and a heavy fraction comprising asphaltenes; inducing in situ precipitation of at least a portion of the asphaltenes within the subsurface formation to produce a precipitated asphaltene material and a mobilized fluid comprising a deasphalted bitumen fraction;
recovering the mobilized fluid as a production fluid comprising the deasphalted bitumen fraction, water, solids and a portion of the asphaltene-precipitating solvent while leaving a majority of the precipitated asphaltene material within the subsurface formation;
separating deasphalted bitumen from the production fluid; subjecting the deasphalted bitumen to a thermal treatment at about or below incipient coking conditions to produce the partially upgraded bitumen product; determining a property of the partially upgraded bitumen product; and adjusting an operating parameter of the thermal treatment based on the determined property of the partially upgraded bitumen product.

[116] According to a possible implementation, all of the precipitated asphaltene material is left within the subsurface formation and the production fluid contains substantially none of the precipitated asphaltene material.

[117] According to a possible implementation, introducing the asphaltene-precipitating solvent into the subsurface formation comprises injecting the asphaltene-precipitating solvent via a horizontal injection well provided in the subsurface formation;
and wherein the production fluid is recovered via a horizontal production well that is located below the horizontal injection well.

[118] According to a possible implementation, the asphaltene-precipitating solvent comprises an alkane solvent.

[119] According to a possible implementation, the alkane solvent comprises propane, butane, pentane, hexane, heptane or a mixture thereof.

[120] According to a possible implementation, the alkane solvent comprises propane.

[121] According to a possible implementation, the alkane solvent comprises butane.

[122] According to a possible implementation, the alkane solvent comprises pentane.

[123] According to a possible implementation, subjecting the deasphalted bitumen to the thermal treatment comprises heating the deasphalted bitumen to a temperature between 200 C and 475 C.

[124] According to a possible implementation, subjecting the deasphalted bitumen to the thermal treatment comprises heating the deasphalted bitumen to a temperature between 350 C and 450 C.

[125] According to a possible implementation, the thermal treatment is performed for a duration of up to 300 minutes.

[126] According to a possible implementation, the thermal treatment is performed for a duration of between 15 minutes and 240 minutes.

[127] According to a possible implementation, the thermal treatment is performed at a pressure between 50 psig and 1500 psig.

[128] According to a possible implementation, the thermal treatment is performed at a pressure between 50 psig and 1000 psig.

[129] According to a possible implementation, separating the deasphalted bitumen from the production fluid comprises removing water and solids from the production fluid.

[130] According to a possible implementation, separating the deasphalted bitumen from the production fluid comprises recovering at least a portion of the asphaltene-precipitating solvent from the production fluid to obtain a recovered asphaltene-precipitating solvent for reintroduction into the subsurface formation.

[131] According to a possible implementation, introducing the asphaltene-precipitating solvent into the subsurface formation comprises vaporizing the asphaltene-precipitating solvent at surface, and injecting the asphaltene-precipitating solvent into the subsurface formation in vapor phase.

[132] According to a possible implementation, conditions of the in situ bitumen recovery operation comprise providing a solvent-to-bitumen ratio of the mobilized fluid that is sufficiently high to cause the in situ precipitation of asphaltenes at operating extraction temperatures and pressures.

[133] According to a possible implementation, the solvent-to-bitumen ratio of the mobilized fluid is sufficiently high to cause substantially all of the asphaltenes to precipitate such that the deasphalted bitumen fraction is fully deasphalted.

[134] According to a possible implementation, the solvent-to-bitumen ratio of the mobilized fluid is provided to cause partial precipitation of asphaltenes such that the deasphalted bitumen fraction comprises a reduced asphaltene content.

[135] According to a possible implementation, the determined property of the partially upgraded bitumen product comprises at least one of asphaltene content of the partially upgraded bitumen product, a compositional characteristic of the partially upgraded bitumen product, a viscosity of the partially upgraded bitumen product, a density of the partially upgraded bitumen product, and an olefin content of the partially upgraded bitumen product.

[136] According to a possible implementation, the process further comprises combining the deasphalted bitumen with a second hydrocarbon material to obtain a combined deasphalted bitumen material that is subjected to the thermal treatment.

[137] According to a possible implementation, combining the deasphalted bitumen with the second hydrocarbon material to obtain the combined deasphalted bitumen material is performed when the property of the deasphalted bitumen is above or below a given threshold.

[138] According to a possible implementation, the second hydrocarbon material comprises a second deasphalted bitumen.

[139] According to a possible implementation, the second deasphalted bitumen is obtained from a second subsurface formation.

[140] According to a possible implementation, the process further comprises subjecting the deasphalted bitumen to an at-surface deasphalting treatment to further reduce the asphaltene content of the deasphalted bitumen prior to the thermal treatment.

[141] According to a possible implementation, the at-surface deasphalting treatment comprises using at least a portion of the recovered asphaltene-precipitating solvent as deasphalting solvent.

[142] According to a possible implementation, the deasphalted bitumen and the second hydrocarbon material are combined in relative proportions so that the combined deasphalted bitumen material has a predetermined composition based on desired operating parameters of the thermal treatment.

[143] According to a possible implementation, the process further comprises combining multiple production fluids respectively obtained from a plurality of in situ recovery wells to form a combined production fluid, and separating the deasphalted bitumen from the combined production fluid.

[144] According to a possible implementation, subjecting the deasphalted bitumen to the thermal treatment comprises maintaining the deasphalted bitumen in liquid phase during the thermal treatment.

[145] According to a possible implementation, maintaining the deasphalted bitumen in liquid phase comprises providing conditions to cause a transfer of hydrogen from the heavy fraction to the light fraction directly in the liquid phase.

[146] According to a possible implementation, the thermal treatment comprises supplying the deasphalted bitumen to a thermal treatment vessel and withdrawing the partially upgraded bitumen product from the thermal treatment vessel as a single stream from a product outlet.

[147] According to a possible implementation, the thermal treatment comprises feeding the single stream of partially upgraded bitumen product to a gas separator and removing at least a portion of a gas phase from the partially upgraded bitumen product.

[148] According to a possible implementation, adjusting the operating parameter of the thermal treatment based on the determined property of the partially upgraded bitumen product comprises adjusting at least one of the temperature, the duration and the pressure of the thermal treatment.

[149] According to a possible implementation, subjecting the deasphalted bitumen to the thermal treatment comprises adding an external source of hydrogen to the deasphalted bitumen.

[150] According to a possible implementation, subjecting the deasphalted bitumen to the thermal treatment comprises adding a hydrogen transfer agent to the deasphalted bitumen.

[151] According to a possible implementation, the external source of hydrogen is a diatomic hydrogen-containing gas.

[152] According to a possible implementation, the hydrogen transfer agent comprises paraffins, naphthenes, naphtheno-aromatics and/or aromatics.

[153] According to a possible implementation, the hydrogen transfer agent comprises at least one of butane, propane, methane, tetralin, decalin, and anthracene.

[154] According to a possible implementation, the hydrogen transfer agent comprises a hydrogen donor.

[155] According to a possible implementation, the hydrogen donor comprises at least one of tetralin, decalin, synthetic crude oil, fractions of synthetic crude oil, tight oil, shale oil and light crude oils.

[156] According to a possible implementation, the process further comprises diluting the partially upgraded bitumen product with a diluent to obtain a diluted bitumen product.

[157] According to a possible implementation, the diluent comprises an aromatic diluent, a naphthenic diluent, natural gas condensates, synthetic crude, a fraction of synthetic crude oil or streams thereof.

[158] According to a possible implementation, the diluted bitumen product is diluted to a predetermined pipeline specification, and is also based on the determined property of the partially upgraded bitumen product.

[159] According to a possible implementation, the process further comprises recovering heat from the partially upgraded bitumen product and reusing at least a portion of the recovered heat in the in situ bitumen recovery operation.

[160] According to a possible implementation, the heat is at least partly reused for pre-heating a process stream that is part of the in situ bitumen recovery operation prior to a unit operation.

[161] According to a possible implementation, the deasphalted bitumen has a variable composition over time.

[162] According to a possible implementation, the deasphalted bitumen has a higher asphaltene content during an earlier stage of the in situ bitumen recovery operation, and a lower asphaltene content during a later stage of the in situ bitumen recovery operation.

[163] According to a possible implementation, the earlier stage comprises a startup stage, and the later stage comprises a normal operation stage of the in situ bitumen recovery operation.

[164] According to a possible implementation, the process further comprises controlling the in situ bitumen recovery operation or the thermal treatment or a combination thereof, based on the variable composition of the deasphalted bitumen.

[165] According to a possible implementation, the thermal treatment is operated at lower severity conditions when the deasphalted bitumen has a higher asphaltene content, and is operated at higher severity conditions when the deasphalted bitumen has a lower asphaltene content.

[166] According to a possible implementation, the thermal treatment is continuously controlled based on the variable composition of the deasphalted bitumen.

[167] According to a possible implementation, the thermal treatment is intermittently controlled based on the variable composition of the deasphalted bitumen.

[168] In accordance with another aspect, there is provided a process for producing a partially upgraded bitumen product. The process comprises conducting an in situ bitumen recovery operation, comprising: introducing an asphaltene-precipitating solvent into a subsurface formation to contact bitumen contained in the subsurface formation, the bitumen comprising a light fraction and a heavy fraction comprising asphaltenes, at conditions to cause in situ precipitation of at least a portion of the asphaltenes within the subsurface formation to produce a precipitated asphaltene material and a mobilized fluid comprising a deasphalted bitumen fraction; recovering the mobilized fluid as a production fluid comprising the deasphalted bitumen fraction, water, solids and a portion of the asphaltene-precipitating solvent while leaving a majority of the precipitated asphaltene material within the subsurface formation; and separating deasphalted bitumen from the production fluid; and subjecting the deasphalted bitumen to a thermal treatment at about or below incipient coking conditions to produce the partially upgraded bitumen product.

[169] According to a possible implementation, the process further comprises determining at least one property of the deasphalted bitumen and/or at least one property of the partially upgraded bitumen product, and adjusting at least one operating parameter of the thermal treatment and/or or the in situ bitumen recovery operation based on the at least one determined property.

[170] According to a possible implementation, all of the precipitated asphaltene material is left within the subsurface formation and the production fluid contains substantially none of the precipitated asphaltene material.

[171] According to a possible implementation, introducing the asphaltene-precipitating solvent into the subsurface formation comprises injecting the asphaltene-precipitating solvent via a horizontal injection well provided in the subsurface formation;
and wherein the production fluid is recovered via a horizontal production well that is located below the horizontal injection well.

[172] According to a possible implementation, horizontal production well and the horizontal injection well are operated according to gravity dominated recovery.

[173] According to a possible implementation, the asphaltene-precipitating solvent comprises an alkane solvent.

[174] According to a possible implementation, the alkane solvent comprises propane, butane, pentane, hexane, heptane or a mixture thereof.

[175] According to a possible implementation, the alkane solvent comprises propane.

[176] According to a possible implementation, the alkane solvent comprises butane.

[177] According to a possible implementation, the alkane solvent comprises pentane.

[178] According to a possible implementation, the thermal treatment is operated at a temperature above 200 C.

[179] According to a possible implementation, the thermal treatment is operated at a temperature above 250 C.

[180] According to a possible implementation, the thermal treatment is operated at a temperature above 300 C.

[181] According to a possible implementation, the thermal treatment is operated at a temperature above 350 C.

[182] According to a possible implementation, the thermal treatment is operated at a temperature above 400 C.

[183] According to a possible implementation, the thermal treatment is operated at a temperature above 450 C.

[184] According to a possible implementation, the thermal treatment is operated at a residence time of up to 300 minutes.

[185] According to a possible implementation, the residence time of the thermal treatment is above 15 minutes.

[186] According to a possible implementation, the residence time of the thermal treatment is above 60 minutes.

[187] According to a possible implementation, the residence time of the thermal treatment is above 90 minutes.

[188] According to a possible implementation, the residence time of the thermal treatment is above 150 minutes.

[189] According to a possible implementation, the residence time of the thermal treatment is above 180 minutes.

[190] According to a possible implementation, the residence time of the thermal treatment is above 210 minutes.

[191] According to a possible implementation, the thermal treatment is operated at a pressure between 50 psig and 1500 psig.

[192] According to a possible implementation, the thermal treatment is operated at a pressure between 50 psig and 1000 psig.

[193] According to a possible implementation, separating the deasphalted bitumen from the production fluid comprises removing water and solids from the production fluid.

[194] According to a possible implementation, separating the deasphalted bitumen from the production fluid comprises recovering at least a portion of the asphaltene-precipitating solvent from the production fluid to obtain a recovered asphaltene-precipitating solvent for reintroduction into the subsurface formation.

[195] According to a possible implementation, introducing the asphaltene-precipitating solvent into the subsurface formation comprises vaporizing the asphaltene-precipitating solvent at surface, and injecting the asphaltene-precipitating solvent into the subsurface formation in vapor phase.

[196] According to a possible implementation, conditions of the in situ bitumen recovery operation comprise providing a solvent-to-bitumen ratio of the mobilized fluid that is sufficiently high to cause the in situ precipitation of asphaltenes at operating extraction temperatures and pressures.

[197] According to a possible implementation, the solvent-to-bitumen ratio of the mobilized fluid is sufficiently high to cause substantially all of the asphaltenes to precipitate such that the deasphalted bitumen fraction is fully deasphalted.

[198] According to a possible implementation, the solvent-to-bitumen ratio of the mobilized fluid is provided to cause partial precipitation of asphaltenes such that the deasphalted bitumen fraction comprises a reduced asphaltene content.

[199] According to a possible implementation, the process further comprises combining the deasphalted bitumen with a second hydrocarbon material to obtain a combined deasphalted bitumen material that is subjected to the thermal treatment.

[200] According to a possible implementation, the second hydrocarbon material comprises a second deasphalted bitumen.

[201] According to a possible implementation, the second deasphalted bitumen is obtained from a second subsurface formation.

[202] According to a possible implementation, the deasphalted bitumen and the second hydrocarbon material are combined in relative proportions so that the combined deasphalted bitumen material has a predetermined composition based on desired operating parameters of the thermal treatment.

[203] According to a possible implementation, the process further comprises combining multiple production fluids respectively obtained from a plurality of in situ recovery wells to form a combined production fluid, and separating the deasphalted bitumen from the combined production fluid.

[204] According to a possible implementation, subjecting the deasphalted bitumen to the thermal treatment comprises maintaining the deasphalted bitumen in liquid phase during the thermal treatment.

[205] According to a possible implementation, maintaining the deasphalted bitumen in liquid phase comprises providing conditions to cause a transfer of hydrogen from the heavy fraction to the light fraction directly in the liquid phase.

[206] According to a possible implementation, the thermal treatment comprises supplying the deasphalted bitumen to a thermal treatment vessel and withdrawing the partially upgraded bitumen product from the thermal treatment vessel as a single stream from a product outlet.

[207] According to a possible implementation, the thermal treatment comprises feeding the single stream of partially upgraded bitumen product to a gas separator and removing at least a portion of a gas phase from the partially upgraded bitumen product.

[208] According to a possible implementation, subjecting the deasphalted bitumen to the thermal treatment comprises adding an external source of hydrogen to the deasphalted bitumen.

[209] According to a possible implementation, subjecting the deasphalted bitumen to the thermal treatment comprises adding a hydrogen transfer agent to the deasphalted bitumen.

[210] According to a possible implementation, the external source of hydrogen is a diatomic hydrogen-containing gas.

[211] According to a possible implementation, the hydrogen transfer agent comprises paraffins, naphthenes, naphtheno-aromatics and/or aromatics.

[212] According to a possible implementation, the hydrogen transfer agent comprises at least one of butane, propane, methane, tetralin, decalin, and anthracene.

[213] According to a possible implementation, the hydrogen transfer agent comprises a hydrogen donor.

[214] According to a possible implementation, the hydrogen donor comprises at least one of tetralin, decalin, synthetic crude oil, fractions of synthetic crude oil, tight oil, shale oil and light crude oils.

[215] According to a possible implementation, the process further comprises diluting the partially upgraded bitumen product with a diluent to obtain a diluted bitumen product.

[216] According to a possible implementation, the diluent comprises an aromatic diluent, a naphthenic diluent, natural gas condensates, synthetic crude, a fraction of synthetic crude oil or streams thereof.

[217] According to a possible implementation, the diluted bitumen product is diluted to a predetermined pipeline specification, and is also based on the determined property of the partially upgraded bitumen product.

[218] According to a possible implementation, the process further comprises recovering heat from the partially upgraded bitumen product and reusing at least a portion of the recovered heat in the in situ bitumen recovery operation.

[219] According to a possible implementation, the heat is at least partly reused for pre-heating a process stream that is part of the in situ bitumen recovery operation prior to a unit operation.

[220] According to a possible implementation, the deasphalted bitumen has a variable composition over time.

[221] According to a possible implementation, the deasphalted bitumen has a higher asphaltene content during an earlier stage of the in situ bitumen recovery operation, and a lower asphaltene content during a later stage of the in situ bitumen recovery operation.

[222] According to a possible implementation, the earlier stage comprises a startup stage, and the later stage comprises a normal operation stage of the in situ bitumen recovery operation.

[223] According to a possible implementation, the process further comprises controlling the in situ bitumen recovery operation or the thermal treatment or a combination thereof, based on the variable composition of the deasphalted bitumen.

[224] According to a possible implementation, the thermal treatment is operated at lower severity conditions when the deasphalted bitumen has a higher asphaltene content, and is operated at higher severity conditions when the deasphalted bitumen has a lower asphaltene content.

[225] According to a possible implementation, the thermal treatment is continuously controlled based on the variable composition of the deasphalted bitumen.

[226] According to a possible implementation, the thermal treatment is intermittently controlled based on the variable composition of the deasphalted bitumen.

[227] In accordance with another aspect, there is provided a system for producing a partially upgraded bitumen product. The system comprises an in situ bitumen recovery facility, comprising: a horizontal injection well located in a subsurface formation and configured for injecting an asphaltene-precipitating solvent into the subsurface formation to contact bitumen contained therein at conditions to cause in situ precipitation of at least a portion of asphaltenes within the subsurface formation to produce a precipitated asphaltene material and a mobilized fluid comprising a deasphalted bitumen fraction; a horizontal production well located in the subsurface formation below the horizontal injection well, thereby forming a well pair, the horizontal production well being configured to recover the mobilized fluid to surface as a production fluid that comprises the deasphalted bitumen fraction, water, solids and a portion of the asphaltene-precipitating solvent while leaving a majority of the precipitated asphaltene material within the subsurface formation; and a surface separation unit in fluid communication with the horizontal production well and configured to separate deasphalted bitumen from the production fluid; and a thermal treatment facility in fluid communication with the in situ bitumen recovery facility, and configured to subject the deasphalted bitumen to thermal treatment at about or below incipient coking conditions to produce the partially upgraded bitumen product.

[228] According to a possible implementation, the system further comprises a measurement unit configured to determine at least one property of the deasphalted bitumen and/or at least one property of the partially upgraded bitumen product, and a control unit configured to receive information from the measurement unit and to adjust at least one operating parameter of the thermal treatment facility and/or or the in situ bitumen recovery facility based on the at least one determined property.

[229] According to a possible implementation, the horizontal production well and the horizontal injection well are configured as a well pair for gravity dominated recovery.

[230] According to a possible implementation, the asphaltene-precipitating solvent comprises an alkane solvent.

[231] According to a possible implementation, the alkane solvent comprises propane, butane, pentane, hexane, heptane or a mixture thereof.

[232] According to a possible implementation, the alkane solvent comprises propane.

[233] According to a possible implementation, the alkane solvent comprises butane.

[234] According to a possible implementation, the alkane solvent comprises pentane.

[235] According to a possible implementation, the thermal treatment facility comprises a thermal treatment vessel configured to receive and thermally treat the deasphalted bitumen.

[236] According to a possible implementation, the thermal treatment vessel is configured to operate at a temperature above 200 C.

[237] According to a possible implementation, the thermal treatment vessel is configured to operate at a temperature above 250 C.

[238] According to a possible implementation, the thermal treatment vessel is configured to operate at a temperature above 300 C.

[239] According to a possible implementation, the thermal treatment vessel is configured to operate at a temperature above 350 C.

[240] According to a possible implementation, the thermal treatment vessel is configured to operate at a temperature above 400 C.

[241] According to a possible implementation, the thermal treatment vessel is configured to operate at a temperature above 450 C.

[242] According to a possible implementation, the thermal treatment vessel is configured to operate at a residence time of up to 300 minutes.

[243] According to a possible implementation, the residence time of the thermal treatment vessel is above 15 minutes.

[244] According to a possible implementation, the residence time of the thermal treatment vessel is above 60 minutes.

[245] According to a possible implementation, the residence time of the thermal treatment vessel is above 90 minutes.

[246] According to a possible implementation, the residence time of the thermal treatment vessel is above 150 minutes.

[247] According to a possible implementation, the residence time of the thermal treatment vessel is above 180 minutes.

[248] According to a possible implementation, the residence time of the thermal treatment vessel is above 210 minutes.

[249] According to a possible implementation, the thermal treatment vessel is configured to operate at a pressure between 50 psig and 1500 psig.

[250] According to a possible implementation, the thermal treatment vessel is configured to operate at a pressure between 50 psig and 1000 psig.

[251] According to a possible implementation, the surface separation unit is further configured to separate water and solids from the production fluid.

[252] According to a possible implementation, the surface separation unit is further configured to recover at least a portion of the asphaltene-precipitating solvent from the production fluid to obtain a recovered asphaltene-precipitating solvent for reintroduction into the subsurface formation via the horizontal injection well.

[253] According to a possible implementation, the in situ bitumen recovery facility comprises a vaporization unit configured to vaporize the asphaltene-precipitating solvent at surface prior to supplying to the horizontal injection well for introduction as a vapor phase.

[254] According to a possible implementation, the thermal treatment facility is configured such that the deasphalted bitumen is maintained in liquid phase during the thermal treatment to cause a transfer of hydrogen from the heavy fraction to the light fraction directly in the liquid phase.

[255] According to a possible implementation, the thermal treatment vessel has a single product outlet for withdrawing the partially upgraded bitumen product from the thermal treatment vessel as a single stream.

[256] According to a possible implementation, the thermal treatment facility further comprises a gas separator configured to receive the single stream of partially upgraded bitumen product and remove at least a portion of a gas phase from the partially upgraded bitumen product.

[257] According to a possible implementation, the thermal treatment facility comprises no external hydrogen addition unit.

[258] According to a possible implementation, the thermal treatment facility comprises an external hydrogen addition unit configured to add an external source of hydrogen to the deasphalted bitumen.

[259] According to a possible implementation, the thermal treatment facility comprises an external hydrogen addition unit configured to add a hydrogen transfer agent to the deasphalted bitumen.

[260] According to a possible implementation, the system further comprises a dilution unit configured to receive the partially upgraded bitumen product from the thermal treatment facility and to dilute the partially upgraded bitumen product with a diluent to obtain a diluted bitumen product.

[261] According to a possible implementation, the system further comprises a heat recovery unit configured to recover heat from the thermal treatment facility and to reuse at least a portion of the recovered heat in the in situ bitumen recovery facility.

[262] According to a possible implementation, the heat is recovered from the partially upgraded bitumen product.

[263] According to a possible implementation, the heat is at least partly reused for pre-heating a process stream of the in situ bitumen recovery facility prior to a unit operation.

[264] According to a possible implementation, the deasphalted bitumen has a variable composition over time.

[265] According to a possible implementation, the deasphalted bitumen has a higher asphaltene content during an earlier stage of operating the in situ bitumen recovery facility, and a lower asphaltene content during a later stage of operating the in situ bitumen recovery facility.

[266] According to a possible implementation, the earlier stage comprises a startup stage, and the later stage comprises a normal operation stage of the in situ bitumen recovery facility.

[267] According to a possible implementation, the system further comprises a control system configured to control the in situ bitumen recovery facility or the thermal treatment or a combination thereof, based on the variable composition of the deasphalted bitumen.

[268] According to a possible implementation, the control system is configured to control operation of the thermal treatment facility at lower severity conditions when the deasphalted bitumen has a higher asphaltene content, and at higher severity conditions when the deasphalted bitumen has a lower asphaltene content.

[269] According to a possible implementation, the control system is configured to continuously control the thermal treatment facility based on the variable composition of the deasphalted bitumen.

[270] According to a possible implementation, the control system is configured to intermittently control the thermal treatment facility based on the variable composition of the deasphalted bitumen.

BRIEF DESCRIPTION OF THE DRAWINGS

[271] Figure 1 is a schematic representation of a process for partially upgrading bitumen, including a well pair including an injection well and a production well located in a subsurface formation and an at-surface thermal treatment stage for treating the deasphalted bitumen separated from the production fluid.

[272] Figure 2 is a flow diagram of a process for treating deasphalted bitumen including a separation step, a thermal treatment and a dilution step.

[273] Figure 3 is a flow diagram of a process for treating a partially deasphalted bitumen stream including a solvent deasphalting step followed by thermal treatment step.

[274] Figure 4 is a flow diagram of a process for treating various streams of deasphalted and partially deasphalted bitumen materials including a thermal treatment step where properties of streams are monitored and the process is controlled.

[275] Figure 5 is a flow diagram of a process for treating a production fluid from an in situ operation, including a separation step, a storage or holding step and a thermal treatment step.

[276] Figure 6 is a flowchart of a control strategy for a process for producing a partially deasphalted bitumen product.

[277] Figure 7 is a flowchart of another control strategy for a process for producing a partially deasphalted bitumen product.

[278] Figure 8 is a process diagram showing an example of a thermal treatment unit and downstream processing.
DETAILED DESCRIPTION

[279] Techniques described herein relate to the recovery and treatment of bitumen and include a subsurface deasphalting treatment to remove at least some asphaltenes from bitumen within the reservoir and recover deasphalted bitumen, followed by an at-surface thermal treatment of the deasphalted bitumen to produce partially upgraded bitumen. The combined treatments of subsurface deasphalting followed by at-surface mild thermal treatment can be globally referred to herein as a "partial upgrading" process.

[280] The deasphalting stage is performed in situ within a subsurface formation, such as an oil sands formation. The subsurface formation can include hydrocarbon materials, water and solids. The bitumen within the formation includes various hydrocarbon components, including heavier asphaltenes and lighter maltenes. Bitumen also includes various non-hydrocarbon compounds (e.g., sulfur, metals, etc.) and micro-carbon residue, which may tend to associate with certain hydrocarbon components of the bitumen such as asphaltenes.

[281] The in situ deasphalting stage uses the injection of a deasphalting solvent, such as propane or butane, at conditions that mobilize bitumen in the reservoir and cause asphaltene precipitation. The deasphalted mobilized bitumen is then recovered as part of a production fluid that also includes solvent, water and solids. The in situ deasphalting stage can employ various well configurations to inject the solvent and recover the production fluid.

[282] The thermal treatment stage is conducted ex situ, i.e., using treatment units that are provided at surface. The deasphalted bitumen separated from the production fluid recovered from an in situ bitumen recovery operation, is supplied to the thermal treatment stage to produce the partially upgraded bitumen.

[283] The partial upgrading process as described herein facilitates modifying certain physicochemical properties of bitumen in order to improve its suitability for pipeline transportation. For instance, precipitating and rejecting asphaltenes in situ within a subsurface formation and thermally treating the deasphalted bitumen can result in a partially upgraded bitumen product having a reduced viscosity and/or density.
The viscosity and density reduction can, in turn, help reduce or eliminate diluent requirements for the partially upgraded bitumen product to meet pipeline specifications. A
non-limiting example of a pipeline specification can require a viscosity of 350 cSt or less at the reference temperature of the pipeline and a density of 940 kg/m3 or less.
Other requirements can also be part of a pipeline specification, such as the olefin content of the bitumen, for instance an olefin content of less than 1 wt% (1-decene equivalent basis). In contrast to deasphalting bitumen using at-surface facilities, subsurface deasphalting can be beneficial since at least a portion of the asphaltenes contained in the bitumen can remain in the subsurface formation, thereby avoiding the need for handling and treatment of asphaltene materials at surface.

[284] The subsurface deasphalting of bitumen can occur in the context of a solvent-assisted gravity drainage operation, where a precipitating solvent (e.g., a paraffinic solvent such as propane or butane) is introduced into a subsurface formation, with or without steam, to facilitate bitumen recovery from the subsurface formation. For a solvent-assisted gravity drainage operation, the well configuration would typically include a horizontal well pair including an injection well overlying a production well. The introduction of the precipitating solvent into the subsurface formation can play several roles, e.g., the solvent can help increase the mobility of the bitumen by dissolution and heating to facilitate drainage of mobilized bitumen toward the production well, and the solvent can induce in situ precipitation of at least a portion of the asphaltene content of the bitumen such that a majority of precipitated asphaltenes remain within the subsurface formation.
The production fluid recovered via the production well can thus include mobilized bitumen that includes a deasphalted bitumen fraction and a portion of solvent.

[285] The solvent to be injected into the subsurface formation can be selected and injected at conditions to facilitate asphaltene precipitation. Asphaltene precipitation is a phenomenon that can depend on temperature, pressure, solvent type and concentration relative to the bitumen, bitumen composition, and other factors. The type of solvent injected into the subsurface formation can be determined at least in part based on the extent of asphaltene rejection that is desired, such that a deasphalted bitumen having given properties can be recovered from the subsurface formation.

[286] Paraffinic solvents, also referred to as alkanes, such as propane, butane, and pentane, are known as having the property of promoting the precipitation of asphaltenes under certain conditions. The solubility of asphaltenes in paraffinic solvents is relatively low, for instance in contrast to the solubility of asphaltenes in aromatic solvents.
Asphaltenes are a component of heavy hydrocarbons that can indeed be defined in accordance with their solubility in given solvents: asphaltenes are defined as dissolving in toluene and precipitating in certain paraffinic solvents (n-alkanes).
Paraffinic solvents that can induce precipitation typically include Cl-C7 paraffins, but higher C-number paraffinic solvents can also be considered as solvents to precipitate asphaltenes under certain conditions. In some implementations, the paraffinic solvents can be propane, butane, or pentane, and mixtures thereof.

[287] The subsurface deasphalting as described herein can produce deasphalted bitumen that can have different levels of asphaltenes. For example, the deasphalted bitumen can be partially deasphalted with a lower or medium range of asphaltene depletion or can be substantially deasphalted. The extent of precipitation of the asphaltenes within the subsurface formation can depend, for instance, on the type of solvent or combination of solvents introduced into the subsurface formation, the asphaltene content in the bitumen, the composition of the asphaltenes, the presence of other components such as resins in the bitumen, the temperature and pressure conditions within the subsurface formation, and the quantity of solvent used, which can be expressed as a solvent-to-bitumen (SIB) ratio. In addition, the extent of deasphalting can vary over time and depend on the stage or operating conditions of the in situ recovery operation, such that the asphaltene content in the produced deasphalted bitumen can also vary over time.

[288] As mentioned above, the production fluid recovered from the production well of the in situ recovery operation includes a deasphalted bitumen fraction as well as other materials, such as solvent, water and solids. The production fluid can be processed in a surface facility to remove water and solids, recover solvent for reinjection into the subsurface formation, and thus produce a deasphalted bitumen stream.

[289] The deasphalted bitumen can then be used as a deasphalted bitumen feedstock in a thermal treatment stage in order to produce the partially upgraded bitumen product. The thermal treatment of the deasphalted bitumen can be performed at temperature and pressure conditions that are below and/or close to incipient coking conditions. In other words, the thermal treatment conditions can be provided to avoid conversion of heavy hydrocarbon components into coke, although some coke precursors can form.

[290] During the thermal treatment, both the heavy and light fractions of the deasphalted bitumen product undergo various reactions, including thermal cracking. The cracking reactions result in the formation of smaller hydrocarbon molecules, which in some implementations can have a positive impact on viscosity reduction and bitumen product quality. "Fraction" as used herein with respect to the thermal treatment step refers to a collection of hydrocarbons that can be recovered and/or processed together.
The fraction can contain, but is not limited to, hydrocarbons that are similar in composition, physical characteristics (e.g., viscosity), boiling point, location, geologic origin, or in recoverability or processability. A heavy fraction as used herein refers to a hydrocarbon fraction having a boiling point above about 525 C. Typically, the heavy fraction can include asphaltenes, if present, along with smaller amounts of resins, aromatics and other hydrocarbon compounds. A light fraction as used herein with respect to the thermal treatment step refers to a hydrocarbon fraction having a boiling point of less than 525 C.
For instance, the light fraction can include hydrocarbon components that are commonly referred to as vacuum gas oil, heavy gas oil, light gas oil and distillates in terms of boiling points.

[291] In some implementations, thermally treating the deasphalted bitumen at temperature and pressure conditions to remain below and/or close to incipient coking conditions can be performed at higher severity conditions than the temperature and pressure conditions necessary for whole bitumen to remain below and/or close to incipient coking conditions. The term "severity" as used herein refers to the severity of the conditions of temperature and residence time at which bitumen is treated. For example, the severity can be expressed in terms of an equivalent reaction time (ERT) in seconds of residence time when a reactor is operating at 427 C (800 F). The ERT
corresponds to the residence time that would achieve the same conversion of heavy material at a given temperature as if the reaction was conducted at 427 C (800 F).

[292] In some implementations, operating the thermal treatment at higher severity conditions but still below the onset of coke formation, can be made possible at least in part because asphaltene rejection within the subsurface formation can facilitate the production of a deasphalted bitumen having a reduced amount of impurities as well as a reduced asphaltene content. Operating the thermal treatment at higher severity conditions can in turn achieve a higher residue conversion, i.e., the 525 C+ residue fraction from deasphalted bitumen can be converted to a greater extent compared to virgin 525 C+
bitumen material due to the subsurface rejection of asphaltenes.

[293] In some implementations, the thermal treatment described herein can be considered as a mild thermal treatment. Examples of operating conditions for a mild thermal treatment include performing the thermal treatment at a temperature between 200 C and 475 C, or between about 250 C and about 450 C. In other implementations, the temperature of the thermal treatment is between about 350 C and about 450 C, between about 350 C
and about 425 C, between about 360 C and about 440 C, or between about 375 C and about 425 C. In some implementations, the gauge pressure to which the bitumen feedstock is subjected to during the thermal treatment is from about 50 psig to about 1500 psig, from about 50 psig to about 1000 psig, or from about 200 psig to 700 psig. In some implementations, the bitumen feedstock is subjected to the thermal treatment for a time period of up to about 3000 minutes, up to about 300 minutes, from about 15 minutes to about 240 minutes, from about 60 minutes to about 240 minutes, or from about 5 minutes to about 60 minutes.

[294] In some implementations, the severity of the thermal treatment is below the severity required for incipient coke formation. In other implementations, substantially no coke is formed during the thermal treatment. In particular, in some implementations, the severity of the thermal treatment can be kept between 900s and 1500s ERT to minimize coke formation. In some implementations, for instance when the asphaltene content of the deasphalted bitumen subjected to thermal cracking is below a given threshold, less asphaltenes are available to contribute to coking, thus contributing to delay the onset of coking and allowing a higher severity thermal treatment to be performed.
Accordingly, in some implementations, the operating conditions of the at-surface thermal treatment following subsurface solvent deasphalting can be increased to between 1500s and 3000s ERT or between1500s and 5000s ERT.

[295] Depending on the extent of asphaltene rejection that occurred within the subsurface formation and thus of the asphaltene content of the recovered deasphalted bitumen, the operating conditions of the thermal treatment can be chosen such that the components of the deasphalted bitumen are substantially maintained in liquid phase during the thermal treatment to enable hydrogen transfer to occur from the heavy fraction to the light fraction.
For example, in some implementations, it may be desirable to retain a portion of the asphaltenes in the deasphalted bitumen, thus producing partially deasphalted bitumen from the reservoir, to promote hydrogen transfer from the heavy fraction to the light fraction. Accordingly, the subsurface solvent deasphalting can be performed at conditions that allow retaining a portion of the asphaltenes in the recovered deasphalted bitumen. In turn, subjecting deasphalted bitumen that includes both a heavy and a light fractions to a thermal treatment at conditions that allow maintaining both the heavy and light fractions in liquid phase can facilitate leveraging the hydrogen content of the heavy fraction by enabling efficient hydrogen transfer from the heavy fraction to the light fraction, contributing to the enrichment of the light fraction with hydrogen, which can have a positive impact on viscosity reduction and bitumen product quality.

[296] The operating parameters of the thermal treatment can be adjusted taking into consideration the characteristics of the deasphalted bitumen used as the feedstock, to obtain partially upgraded bitumen according to given specifications.
Controlling various parameters influencing the production of the deasphalted bitumen, including adjusting the operating parameters of the subsurface deasphalting to influence the precipitation of the asphaltenes within the formation and/or adjusting a property of the recovered deasphalted bitumen, can also contribute to obtaining deasphalted bitumen having given characteristics, which in turn can allow the operation of the thermal treatment to be such that the partially upgraded bitumen also has given characteristics.

[297] As mentioned above, variation in the asphaltene content of the deasphalted bitumen product can also influence the desirability for the addition of an external source of hydrogen or of a hydrogen transfer agent during the thermal treatment so as to produce a partially upgraded bitumen according to given characteristics. For instance, in some implementations, when the deasphalted bitumen has a low asphaltene content, the severity of the thermal treatment can be controlled higher, or a hydrogen transfer agent can be added during the thermal treatment to reduce the formation of by-products such as olefins and/or to delay the onset of coke formation. In other implementations, when the deasphalted bitumen has an asphaltene content above a given threshold, the thermal treatment can be performed at a lower severity, in which case the addition of a hydrogen transfer agent can be omitted or added in a lesser amount than when the asphaltene content is below the given threshold. Thus, asphaltene content of the deasphalted bitumen can be measured upstream of the thermal treatment and the measured value can be used to control the process parameters of the thermal treatment (e.g., temperature, residence time, hydrogen addition, hydrogen transfer agent addition, and so on).

[298] In some implementations, both of the approaches mentioned above to control and adjust the operating conditions of the thermal treatment and those related to the production of deasphalted bitumen, as well as the adjustments with regard to the characteristics of the recovered deasphalted bitumen, can be combined to allow additional opportunities for maintaining performance and/or fine-tuning of the partial upgrading operations such that given characteristics of the partially upgraded bitumen product can be obtained. Thus, both the in situ deasphalting stage and the thermal treatment stage can be controlled based on various measurements and design parameters in order to coordinate the two stages.

[299] The partially upgraded bitumen obtained following thermal treatment can be removed from a thermal treatment vessel as a single stream that includes all of the hydrocarbon components. In some implementations, the single stream of partially upgraded bitumen product can then be subjected to separation steps to produce various streams, such as one or more light fractions and one or more heavy fractions.
The light fractions can include naphtha, distillate, and/or gasoil, and the heavy fraction can include material having a boiling point above 525 C. It should be noted that the separation of the partially upgraded bitumen product stream can be performed using multiple separation units arranged in series so that downstream separation units receive one or more of the output streams of an upstream unit.

[300] In some implementations, the thermal treatment can also be conducted such that a low quantity of non-condensable hydrocarbon gas is generated. Thus, the partially upgraded bitumen product can be a substantially liquid-phase stream with a minor amount of non-condensable gas (e.g., less than 5 wt%), which can be removed prior to subsequent processing or storage.

[301] Figure 8 illustrates an example implementation of the thermal treatment followed by some downstream processing, and will be described in more detail further below.
Subsurface solvent deasphalting followed by thermal treatment implementations

[302] Techniques described herein facilitate partially upgrading bitumen and include producing deasphalted bitumen using an in situ solvent-assisted recovery process and then subjecting the deasphalted bitumen to thermal treatment.

[303] The in situ solvent-assisted recovery process can include various processes and well configurations for introducing solvent into the reservoir to help mobilize bitumen. The in situ solvent-assisted recovery process can use steam-solvent co-injection, pure solvent injection, solvent-dominated injection with some other fluids being co-injected, methods that utilize solvent injection as well as in situ heating via downhole heaters (e.g., electric resistive heaters, electromagnetic heaters, fluid circulation heaters) or concurrent or sequential combinations of different processes. The solvent can be vaporized at surface for injection, for instance to be injected as superheated solvent which may be at different degrees of superheat, vaporized in situ with heaters as it enters the reservoir, or injected as a liquid in some scenarios.

[304] The in situ process can utilise a horizontal well pair that includes an upper injection well and a lower production well vertically spaced apart from the injection well.
Alternatively, the in situ process can use a single well that is operated cyclically between injection and production modes. Other well configurations and processes are also possible.

[305] While various processes can be used, certain conditions that are provided in the subterranean formation can cause some degree of in situ asphaltene precipitation. Thus, the solvent should be selected and provided in sufficient amount under extraction conditions such that some of the solvent dissolves the bitumen and induces precipitation of asphaltenes in situ. The mobilized bitumen, which has a reduced asphaltene content, then reports to the production well and is pumped to the surface. The deasphalted bitumen is characterized at least by having a reduced asphaltene content compared to its native state. Bitumen having a reduced asphaltene content can facilitate performance of subsequent upgrading treatments, such as the thermal treatment described herein.

[306] In situ deasphalting of bitumen contained in an oil sands formation will now be described in further detail with reference to the figures.

[307] Figure 1 shows a solvent-assisted in situ recovery process to mobilize bitumen and produce mobilized bitumen. The solvent-assisted recovery process can include a well pair provided in a subsurface formation 26, the well pair having an injection well 10 and a production well 16. The injection well 10 and the production well 16 are generally parallel and separated by an interwell region 22. The injection well 10 includes a vertical portion 12 and a horizontal portion 14 extending from the vertical portion 12, and the production well 16 includes a vertical portion 18 and a horizontal portion 20 extending from the vertical portion 18. Alternatively, the solvent-assisted recovery process can be performed using a single horizontal or vertical well that is operated cyclically between injection and production modes.

[308] The solvent-assisted recovery process can also use various other well configurations and operating schemes. In addition, the solvent-assisted recovery process can inject relatively pure solvent in liquid or vapour phase where the solvent is provided as a vapour at surface or is vaporized downhole using a heater provided in the injection well. The solvent-assisted recovery process can use a combination of steam and solvent that are co-injected into the subsurface formation. For steam-solvent co-injection, the steam and solvent can be combined at surface and can have relative quantities such that solvent is the dominant component.

[309] The solvent-assisted recovery process can include various stages, including a startup stage, a normal operation stage, and a mature or wind-down stage. When solvent is injected during a startup phase of the solvent-assisted recovery process, the startup solvent can be different than the solvent injected during the normal operation stage and the mature stage. In some implementations, the solvent used during the startup stage is selected to mobilize hydrocarbons and establish fluid communication, for instance between the injection well and the production well of the well pair. The solvent used during the startup stage can be a solvent that is less likely to induce asphaltene precipitation or that would not induce precipitation, since it can be desirable to avoid such precipitation in proximity to the injection well and/or the production well, i.e., in the interwell region, to avoid impairing the flow of the mobilized bitumen and clogging of the wells.
Aromatic solvents, such as toluene, xylene and diesel, are examples of solvents that can be used during the startup stage to mobilize bitumen while avoiding asphaltene precipitation.

[310] The solvent-assisted recovery process generally transitions to the normal operation stage of the solvent-assisted recovery process once fluid communication between the injection well and the production well has been established, and the development of a solvent chamber has been initiated, i.e., following the startup stage. For a gravity drainage process using a well pair, the normal operation stage can be considered a stage during which mobilized bitumen is recovered to the surface as a production fluid and a solvent chamber grows upward and outward from the injection well. According to the techniques described herein, the solvent introduced into the subsurface formation during the normal operation stage can be chosen so as to include an asphaltene-precipitating solvent to induce precipitation of asphaltenes within the subsurface formation. At least a portion of the precipitated asphaltenes can thus remain within the subsurface formation, such that the production fluid comprising a deasphalted bitumen fraction can be recovered to the surface. Most or a substantial portion of the precipitated asphaltenes can remain deposited within the subsurface formation during the recovery process and even after the recovery process has been completed. However, in some scenarios, asphaltenes that have previously precipitated in the subsurface formation and that have been left in the solvent chamber can be carried down by draining fluids into the pool of mobilized bitumen in proximity of the production well and can be produced along with the production fluid. In such scenarios, asphaltene precipitates can thus be entrained in the production fluid along with the deasphalted bitumen fraction. Whether some asphaltene precipitates are entrained into the production fluid can depend on various factors, such as drainage rates, fluid properties, geological properties of the reservoir, and characteristics of the precipitated asphaltenes.

[311] It is also noted that the "majority" of asphaltene precipitates that form within the formation are left in the formation during the in situ recovery process as described herein.
This means that during the deasphalting in situ recovery process, most of the precipitated asphaltenes remain in the formation and only a minor portion could be recovered with the production fluid. However, it is possible to perform an additional process after the deasphalting in situ recovery process in order to recover a further amount of the precipitated asphaltenes that were left in the formation, of course using an alternative recovery process. If such an additional recovery process were implemented, it could enable the recovery of asphaltenes that were previously precipitated such that the overall amount of precipitated asphaltenes left in the formation after the additional recovery process would not be a majority of the originally precipitated asphaltenes. In other words, while a majority of the asphaltene precipitates are left in the formation during the deasphalting in situ recovery process, these asphaltene precipitates could be recovered later using other recovery processes and thus do not have to remain in the reservoir indefinitely.

[312] In some implementations, a combination of solvents can be used, for instance a combination of solvents comprising at least one asphaltene-precipitating solvent and another solvent such as an aromatic solvent. However, when an aromatic solvent is present, the overall combination of solvents is one that allows precipitation of at least a portion of the asphaltenes within the subsurface formation.

[313] In some implementations, the production fluid and/or the deasphalted bitumen fraction recovered to the surface can have a variable asphaltene content over time. For instance, when transitioning from the startup stage to the normal operation stage, the production fluid can include a decreasing amount of asphaltenes as the deasphalting solvent content within the reservoir and in the production fluid increases.
For example, one factor that can influence the level of deasphalting over time can be the type of startup process used prior to the beginning of the normal operation stage. For instance, for startup processes that include injecting an aromatic solvent into the subsurface formation, the level of deasphalting can range from a zero-deasphalted bitumen during startup and at the beginning of the normal operation stage to a fully-deasphalted bitumen as the deasphalting solvent is used in higher concentrations over time. For startup processes that include injecting or circulating steam as a mobilizing fluid and/or providing heat to the interwell region (e.g., through electric resistive heaters, RF heaters or other heating means), the level of deasphalting can also increase over time from the startup stage with little to no deasphalting to the normal operation stage when deasphalting solvent is used, since such types of startup processes do not cause deasphalting and can result in a high amount of asphaltenes in the production fluid during startup.

[314] In contrast, for startup processes that include injecting a paraffinic solvent into the subsurface formation at elevated concentrations, the level of deasphalting can be more constant over time, since deasphalting can occur during the startup process, such that the transition to the normal operation stage occurs with less fluctuations in terms of asphaltene content in the production fluid. In other scenarios, a deasphalting solvent could be used for startup at certain concentrations and startup conditions that would enable deasphalting, and then deasphalting solvent could be used at alternative conditions (e.g., lower solvent concentrations or different temperature conditions) during the normal operation stage such that less deasphalting would occur during normal operation compared to startup. While various implementations are possible to result in varying levels of deasphalting over time, it is noted that using a low or non deasphalting startup method followed by higher deasphalting for normal operation can be preferred.

[315] Once the solvent-assisted recovery process has been in operation for a certain period of time and the recovery rate of the hydrocarbon production has started to decrease to uneconomical levels, the subsurface formation can be said to transition to a mature subsurface formation. Variables other than the recovery rate can also be indicative of a subsurface formation that has reached a mature stage. Wind-down strategies can then be put in place to manage the mature subsurface formation.

[316] As mentioned above, the techniques described herein can allow for a majority of the precipitated asphaltenes remain in the subsurface formation such that a production fluid that comprises a deasphalted bitumen fraction can be produced to the surface.
It should be noted that, in some implementations, techniques can be put in place to recover at least some of the precipitated asphalted to the surface, for instance for further treatment.

[317] Referring back to Figure 1, the solvent-assisted recovery process is shown in a normal operation stage, where the solvent includes or consists substantially of an asphaltene-precipitating solvent 24, such as a paraffinic solvent, and contributes to the precipitation and deposition of asphaltenes within the subsurface formation 26. In some implementations, the choice of asphaltene-precipitating solvent 24 as well as its concentration are factors that can be varied to produce deasphalted bitumen 54 having given characteristics. The concentration of the asphaltene-precipitating solvent 24 is chosen such that once in the subsurface formation 26, this concentration is sufficient to allow asphaltene precipitation. Other factors such as pressure and temperature of the solvent chamber that forms within the subsurface formation 26, and composition of the hydrocarbon content in the subsurface formation 26, can also influence asphaltene precipitation.

[318] In some implementations, when a substantially pure paraffinic solvent is used as the asphaltene-precipitating solvent 24, the extent of asphaltene precipitation can be higher than when the asphaltene-precipitating solvent 24 includes a combination of different solvents, for instance a combination of a paraffinic solvent and a non-paraffinic solvent, such as an aromatic solvent (e.g., toluene, diesel, xylene). Combining different solvents to obtain the asphaltene-precipitating solvent 24 can be a useful approach to leverage advantages of the respective solvents. In implementations where the asphaltene-precipitating solvent 24 includes steam, e.g., for a solvent-steam recovery process, the produced mobilized bitumen may also be deasphalted to a lesser extent, as less solvent may be injected into the reservoir, and mobilizing heat is being provided at least in part by the steam.

[319] The degree of deasphalting of the produced bitumen can also vary depending on the moment when the mobilized bitumen is produced during the operation of the solvent-assisted recovery process. For instance, when the mobilized bitumen is produced shortly after the startup stage, the solvent content can be lower than later on during the normal operation stage, and the degree of deasphalting of the produced mobilized bitumen can thus be lesser compared to the degree of deasphalting of produced mobilized bitumen obtained later on, after continued injection of the asphaltene-precipitating solvent into the subsurface formation. In other words, when the asphaltene-precipitating solvent has been injected over a longer period during the course of the normal operation stage, the larger solvent content in the extraction chamber can contribute to an increased precipitation and deposition of the asphaltenes within the subsurface formation.

[320] It is to be noted that a subsurface formation represents a partially uncontrolled environment, and certain characteristics of the subsurface formation can also influence the extent of in situ asphaltene precipitation and deposition that occurs within the subsurface formation. Each subsurface formation has its own characteristics, for instance with regard to the type of geological formation, the presence or absence of water zone(s) and/or of reservoir compartments, sedimentary facies, and the porosity and geology of the subsurface formation. In some implementations, appropriate subsurface deasphalting strategies taking into consideration the heterogeneity of the subsurface formation can thus be put in place such that the produced deasphalting bitumen is upgraded according to given criteria.

[321] In addition, the composition of bitumen can vary depending on its location in the subsurface formation, for instance due to lateral variability, i.e., when the bitumen is located higher up in the formation than deeper in the formation, and can also vary along certain depositional breaks. Thus, depending on the location from which the bitumen is mobilized and drained to the production well (e.g., as the operation of the well pair operation progresses through time), deasphalting conditions can be adjusted to once again recover a produced deasphalted bitumen that is deasphalted according to given criteria.

[322] Still referring to Figure 1, a production fluid 28 is recovered at surface and includes a deasphalted bitumen fraction, water, solids and asphaltene-precipitating solvent 24. The production fluid 28 is then subjected to separation 48 to separate deasphalted bitumen 54 from the production fluid 28.

[323] The separation 48 can be a single separation step or can include a series of separation steps. The separation 48 can be implemented for instance to separate water, solids, solvent, and/or non-condensable gas from the production fluid 28. The solvent separation can be useful to recover a portion of the asphaltene-precipitating solvent 24 that has been previously introduced into the formation 26 for mobilizing and deasphalting the bitumen. The recovered solvent can then be reintroduced into the formation 26 to be re-used as the asphaltene-precipitating solvent 24.

[324] With reference to Figures 1 and 2, a recycled asphaltene-precipitating solvent stream 50 is separated from the production fluid 28, and a stream comprising water and solids 52 is also recovered. Again, the separation 48 can include multiple steps that separate different components from the production fluid sequentially, for example. The separation 48 can leverage mechanisms such as gravity separation and evaporative separation to remove different components from each other.

[325] After the separation step 48, the deasphalted bitumen 54 is transported to a thermal treatment unit 56 to be thermally treated and produce the partially upgraded bitumen product 58. The separation 48 can be provided to obtain deasphalted bitumen that has desirable characteristics prior to being subjected to the thermal treatment 56, for instance to obtain given proportions of certain components such that the thermal treatment can be optimized to obtain a partially upgraded bitumen product also having given characteristics, such as with regard to its pipelinability. The separation step 48 can thus be controlled based on desired properties of the deaspalted bitumen feedstock that is supplied to the thermal treatment 56.

[326] Still referring to Figure 1, the stream of deasphalted bitumen 54 is then subjected to the thermal treatment 56 at surface. In some implementations, the at-surface thermal treatment 56 using subsurface deasphalted bitumen 54 as an input stream may benefit from heightened control to account for the variability in the properties (P) of the production fluid 28 and in the deasphalted bitumen 54. For instance, as noted above, the deasphalted bitumen can have a variable asphaltene content, especially during the transition from the startup stage to the normal operation stage. One or more properties (P) of the deasphalted bitumen 54 can be measured and determined, and then the thermal treatment 56 can be controlled accordingly. Control strategies can include controlling hydrogen injection, pre-treating or mixing the produced deasphalted bitumen product with other hydrocarbon streams, for instance to obtain a more consistent composition of the feedstock subjected to the thermal treatment, or regulating operating conditions of the thermal treatment unit.
Possible control strategies are discussed in further detail below.

[327] With reference to Figure 2, in some implementations, the partially upgraded bitumen product 58 can be subjected to a dilution step 60, where a diluent 62 from a diluent supply 64 is added to the partially upgraded bitumen product 58 to produce a diluted bitumen product 66. In some implementations, the diluted bitumen product 66 is diluted so as to meet pipeline specifications. Examples of diluents include a hydrotreated naphtha or a naphthenic diluent. The quantity of diluent that is added can be kept to a minimum by implementing the techniques described herein which provides an opportunity to thermally treat a subsurface deasphalted bitumen product at higher severity conditions than whole bitumen. For instance, in some implementations, the need for diluent addition can be reduced to between 10 vol.% to 20 vol.%, and even to less than about 10 vol.%
per blended diluted bitumen barrel to meet pipeline specifications, compared to about 35 vol.%
of diluent per blended diluted bitumen barrel for whole bitumen.

[328] With reference to Figure 3, in some implementations, the deasphalted bitumen 54 can be further deasphalted if desired, i.e., the deasphalted bitumen 54 can be subjected to an at-surface deasphalting step 68 to further precipitate asphaltenes. In such implementations, an asphaltene-precipitating solvent 70 from a solvent supply 72 is fed to a solvent deasphalting unit, and a deasphalted bitumen 154 stream and an asphaltenes-enriched stream 74 are produced. The resulting deasphalted bitumen 154 can then be subjected to the thermal treatment 56. In some implementations, however, all of the desired level of deasphalting is performed in situ and no subsequent at-surface deasphalting is subsequently performed.

[329] In some implementations, the deasphalted bitumen 54 can be supplied as a feed stream continuously to the thermal treatment 56. The operating conditions of the thermal treatment 56 can be adjusted taking into consideration the properties of the deasphalted bitumen 54 being fed as a direct feed stream, for instance to a thermal treatment unit. For instance, the temperature and the pressure at which the thermal treatment unit is operated, and the residence time of the deasphalted material within the thermal treatment unit, are variables of the thermal treatment that can be adjusted. In one implementation, the output of the separation vessel that produces the deasphalted bitumen 54 can be fluidly connected via pipeline to the input of the thermal treatment unit.
Alternatively, a surge tank and appropriate pumping equipment can be provided along the pipeline. The feed line can be configured such that the thermal treatment unit receives only the deasphalted bitumen 54 as a feedstock.

[330] With reference now to Figure 4, the deasphalted bitumen 54 can optionally be subjected to a blending step 55 to obtain a combined deasphalted bitumen material 57 that is fed to the thermal treatment 56. For instance, the deasphalted bitumen 54 can be blended with a second hydrocarbon material 53 to obtain the combined deasphalted bitumen material 57. The second hydrocarbon material 53 can have a different composition than the deasphalted bitumen 54. In some implementations, the deasphalted bitumen 54 is blended with a second hydrocarbon material 53 when the deasphalted bitumen 54 has a viscosity that is above or below a given viscosity threshold.
For instance, the deasphalted bitumen 54 can be obtained from a formation that is at an earlier stage of operation, while the second hydrocarbon material 53 can be obtained from a formation that is at a later stage of operation, so as to obtain the combined deasphalted bitumen material 57. Thus, a stream with higher asphaltene content can be combined with a stream having lower asphaltene content. In such implementations, the combined deasphalted bitumen material 57 can have properties that result from the respective properties of the deasphalted bitumen 54 and the second hydrocarbon material 53.

[331] Properties (P) of various streams can be monitored and the measurements can be used for process control. For example, properties (P) of the deasphalted bitumen 54 or of the combined deasphalted bitumen material 57 subjected to the thermal treatment 56 can be monitored. Properties (P) of the partially upgraded bitumen product 58 can also be determined. Once these properties are analyzed and depending on the deviation from desired specifications, operating parameters of the thermal treatment 56 can be controlled using a controller 80 in order to thermally treat the feed material in such a way that the characteristics of the partially upgraded bitumen product 58 are within given specifications.
Parameters of the thermal treatment 56 that can be adjusted include temperature, pressure and duration of the thermal treatment 56. In some implementations, a separation step 59 can also follow the thermal treatment 56 to separate the partially upgraded bitumen product 58, for instance, into a thermally treated heavy stream 61 and a thermally treated light stream 63.

[332] With reference now to Figure 5, in some implementations, the deasphalted bitumen 54 can be directed to a holding tank 70, to allow a given volume of deasphalted bitumen 54 to accumulate and be stored in the holding tank 70 prior to being fed to the thermal treatment 56. Storing a given volume of the deasphalted bitumen 54 that will subsequently be used as a feedstock for the thermal treatment step 56 can facilitate monitoring the properties of that given volume of deasphalted bitumen 54, and can also facilitate attenuating variations in the deasphalted bitumen stream 54 such that a more uniform feed to the thermal treatment 56 can be provided. Having a given volume of deasphalted bitumen 54 with known properties can facilitate the operation and/or optimization of the thermal treatment 56 taking into consideration these known properties. In such implementations, benefits of conducting subsurface deasphalting such that precipitated asphaltenes remain within the subsurface formation can be combined with those of supplying a deasphalted product that has known and given characteristics to thermal treatment, thus facilitating operation of the thermal treatment 56 under predetermined or constant operating parameters instead of being reactive to variable characteristics of a continuous incoming stream of deasphalted bitumen 54. This approach can contribute to maintaining the performance of the thermal treatment 56.

[333] Still referring to Figure 5, properties (P) of the deasphalted bitumen 54 stored in the holding tank 70 can be monitored to obtain data on the properties of the stored deasphalted bitumen 71. The properties (P) of streams and materials upstream of the thermal treatment 56 can be used for feed-forward control of the thermal treatment unit.
On the other hand, properties (P) of the partially upgraded bitumen product 58 can also be monitored and can be used for feedback control. In fact, various feedback and feed-forward control strategies can be implemented.

[334] For instance, measurements that enable determining asphaltene content, composition and viscosity of the stored deasphalted bitumen 71 and/or the partially upgraded bitumen product 58 can be obtained and analyzed. Once such information is available, feedback control adjustments 76 can be performed at relevant locations such that given characteristics of the stored deasphalted bitumen 71 and/or the partially upgraded bitumen product 58 can be obtained, for instance by adjusting parameters of the separation step 48, and/or by adjusting the addition of the second hydrocarbon material 53. Feedback control adjustments 76 can also be implemented to control the operating parameters of the thermal treatment 56 in accordance with the properties of the stored deasphalted bitumen 71 and/or the partially upgraded bitumen product 58.
Dilution of the thermally treated deasphalted bitumen stream

[335] Referring back to Figure 2, the partially upgraded bitumen product 54 can be subjected to a dilution step 60 to produce a diluted bitumen product 66. The partially upgraded bitumen product 54 can be diluted to a predetermined pipeline specification.
Examples of diluent include a hydrotreated naphtha or a naphthenic diluent.

[336] As mentioned earlier, the quantity of diluent added can be kept to a minimum by implementing the techniques described herein which provide an opportunity to thermally treat a subsurface deasphalted bitumen product at higher severity conditions than whole bitumen. For instance, in some implementations, the need for diluent addition can be reduced to about 10 vor/o per blended diluted bitumen barrel to meet pipeline specifications, compared to about 35 vol.% of diluent per blended diluted bitumen barrel for whole bitumen. In some implementations, the need for diluent addition can be reduced to less than about 10 vol% per blended diluted bitumen barrel to meet pipeline specifications.
Heat transfer and integration

[337] In some implementations, the heat generated during the thermal treatment 56 can be used to pre-heat certain streams in an in situ processing facility. For instance, the heat generated during the thermal treatment 56 as described herein can be used to preheat the asphaltene-precipitating solvent 54 prior to its injection into the subsurface formation.
This could be accomplished by feeding the recovered solvent and the hot partially upgraded bitumen through an indirect heat exchanger so that the partially upgraded bitumen can be cooled while the solvent is heated. The solvent can require heating for reinjection while the partially upgraded bitumen can require cooling prior to storage. The heat generated during the thermal treatment 56 can also be used to heat other units, streams or heat transfer fluids that are part of the in situ processing facility.

[338] Although the process implementations as described herein and corresponding parts thereof have certain process configurations as explained and illustrated herein, not all of these components and process configurations are essential and thus should not be taken in their restrictive sense. It is to be understood that other suitable components and processing configurations can optionally be used for the process implementations for partially upgrading bitumen as described herein.
Control strategies ¨ adjusting operating conditions of the thermal treatment

[339] Figure 6 shows an example of a control strategy 200 for an implementation of the partial upgrading techniques combining subsurface deasphalting followed by thermal treatment as described herein. In this implementation of the control strategy 200, one objective is to modulate the operating parameters of the thermal treatment to take into account possible variability in the properties of the deasphalted bitumen being fed to the thermal treatment, such that a partially upgraded bitumen product having given characteristics can be obtained.

[340] The control strategy 200 includes the initial step of recovering deasphalted bitumen 228 using an in situ solvent-assisted recovery process. The deasphalted bitumen can optionally be subjected to a blending step and/or a separating step 230. The blending step can include blending together the deasphalted bitumen with one or more hydrocarbon materials to obtain a combined deasphalted material, the combined deasphalted material having a desired property such as a given asphaltene content. A separation step can be implemented to separate solvent from the deasphalted bitumen. It is noted that other components, such as water and solids, are removed from the production fluid to produce the deasphalted bitumen. When solvent is separated from the deasphalted bitumen, the recovered solvent can be re-used as the asphaltene-precipitating solvent to be reintroduced into the subsurface formation.

[341] The deasphalted bitumen, optionally following the blending and/or separation step 230, is then subjected to a mild thermal treatment 232, for instance in a thermal treatment unit, at given operating conditions to produce a partially upgraded bitumen product. The partially upgraded bitumen product is removed 234 from the thermal treatment unit, either as a single stream or as one of multiple streams, and one or more characteristics of the partially upgraded bitumen product are determined 236. Example characteristics of the partially upgraded bitumen product that can be determined can relate to its pipelinability, such as its viscosity, density and composition.

[342] If it is determined that the partially upgraded bitumen product is suitable for pipeline transport or that the characteristics of the partially upgraded bitumen product meet a predetermined specification, it can be decided that the thermal treatment can continue to operate according to similar operating conditions unless a significant change were to occur upstream of the thermal treatment. On the other hand, if it is determined that the partially upgraded bitumen product is not suitable for pipeline transport or that its characteristics do not meet a predetermined specification, the operating conditions of the thermal treatment can be modified accordingly 238.

[343] Changes that can be made to the operation of the thermal treatment include adjusting the temperature and/or pressure at which it is conducted and adjusting the duration of the thermal treatment. Another option is to proceed with a separation step 242 to recover a thermally treated light stream and a thermally treated heavy stream.

[344] Yet another option, for instance if it is determined that the amount of coke formed during the thermal treatment is above a certain threshold, is to perform the thermal treatment in the presence of a hydrogen transfer agent or an external source of hydrogen 240 to delay the onset of coke formation. A hydrogen transfer agent as described herein refers to agents that can be added to be present during the thermal treatment to inhibit coke formation and encourage hydrogen transfer, for instance from the heavy fraction to the light fraction. Hydrogen transfer agents can have the effect of increasing the time and temperature conditions at which incipient coking begins, thus enabling longer residence times or higher temperatures while still inhibiting coke formation. Such agents can be, for instance, methane, propane, butane and anthracene. Among possible hydrogen transfer agents are a class of compounds referred to as hydrogen donors. These hydrogen donors are able to donate hydrogen atoms to other compounds. Examples of hydrogen donors include, for instance, compounds such as tetralin, decalin, light crude oil, synthetic crude oil and fractions thereof, shale oil and tight oil. For clarity, it should be noted that hydrogen transfer agents, including hydrogen donors, are considered distinct from what is referred to herein as an external source of hydrogen, such as diatomic hydrogen (H2) containing gas.

[345] In some implementations, the presence of some asphaltenes in the deasphalted bitumen can facilitate the transfer of hydrogen from the heavy fraction to a lighter fraction during thermal treatment, and can help reduce or avoid the rejection of hydrogen as part of a non-condensable gas phase product. This hydrogen transfer can reduce or eliminate the amount of external diatomic hydrogen addition required to achieve target quality specifications of the thermally treated bitumen product, such as the product's viscosity, density and olefin content. Thus, in some implementations, it can be desirable to keep a certain level of asphaltenes in the deasphalted bitumen that is produced such that these asphaltenes can contribute to the transfer of hydrogen from the heavy fraction to the lighter fraction.

[346] In some implementations, the addition of an external source of hydrogen is not required to achieve target quality specifications of the partially upgraded bitumen product.
This is in contrast with typical thermal processes, in which significant cracking of the bitumen stream occurs, resulting in chemically bonded hydrogen in the bitumen feedstock being rejected to the gas phase. Consequently, in typical thermal processes, the liberation of hydrogen within a high hydrogen content non-condensable gas (e.g., a gas phase including diatomic hydrogen and methane) typically results in a hydrogen-to-carbon ratio in the thermally cracked liquid hydrocarbon product that is lower than or comparable to the hydrogen-to-carbon ratio of the feed. Lower hydrogen-to-carbon ratios is not desirable since one objective of partial upgrading is to increase the hydrogen-to-carbon ratio of the product. Thus, in some implementations, the operating conditions of the thermal treatment are chosen such that a balance is found between hydrogen transfer and thermal cracking of the hydrocarbons, while avoiding or minimizing external hydrogen addition, coking and/or olefin formation.

[347] Of course, any other parameters that can influence the characteristics of the output stream recovered following the thermal treatment can be contemplated such that the thermal treatment can be adapted to produce a partially upgraded bitumen product suitable for pipeline transport. Once the partially upgraded bitumen product is determined to have desired properties, the partially upgraded bitumen product can be supplied to pipelining or storage 244.
Control strategies ¨ Adjusting properties of deasphalted bitumen

[348] Figure 7 shows an example of another control strategy 300 for the implementation of the partial upgrading techniques combining subsurface deasphalting followed by a thermal treatment as described herein. In this implementation of the control strategy 300, one objective is to characterize the properties of the deasphalted bitumen and to modify these properties upstream of the thermal treatment so as to reduce the variability in the operating parameters of the subsequent thermal treatment. Modifying the properties of the deasphalted bitumen can include directly modifying the characteristics of the deasphalted bitumen, such as composition by blending different streams together, and/or adjusting the operating parameters of the subsurface deasphalting process.

[349] The control strategy 300 includes the initial step of recovering deasphalted bitumen 328 using a solvent-assisted recovery process. The deasphalted bitumen can then be characterized in a characterizing step 330 to determine various properties of the deasphalted bitumen, e.g., density, viscosity, composition, and so on. If the properties of the deasphalted bitumen are determined to be desirable, the deasphalted bitumen can be subjected to the thermal treatment 336.

[350] If the properties of the deasphalted bitumen are not desirable or are not within a predetermined operating window, then these properties can be directly adjusted in a blending and/or separation step 332. If a solvent separation step is performed, the recovered solvent 342 can be re-used as the asphaltenes-precipitation solvent to be reinjected into the subsurface formation. For example, solvent recovery from the deasphalted bitumen can be adjusted to recover more or less solvent. Blending can be performed to adjust the asphaltene content or other properties.

[351] In addition, if the properties of the deasphalted bitumen are not desirable, a variable related to the subsurface deasphalting can be adjusted 334, such as the type or composition of the asphaltene-precipitating solvent introduced in the subsurface formation, adjusting the solvent-to-bitumen ratio, adjusting the downhole temperature, adjusting the solvent injection rate, and so on. For example, if lower asphaltene levels in the deasphalted bitumen are desired, then the in situ conditions can be modified (e.g., by using a solvent that has a higher tendency to precipitate asphaltenes at certain solvent-to-bitumen ratios, injecting solvent at higher rates into the formation, or changing the heat that is provided to the formation via the solvent or downhole heaters) in order to increase in situ precipitation and therefore decrease the asphaltene content in the deasphalted bitumen.

[352] Once it is determined that the deasphalted bitumen has the desired properties, the deasphalted bitumen is subjected to the thermal treatment 336, for instance in a thermal treatment unit, to produce the partially upgraded bitumen product. The partially upgraded bitumen product then undergoes a removal step 340 from the thermal treatment unit.
Depending on the type of thermal treatment unit that is used, the removal step can take various forms. In some implementations, the removal step 340 is performed such that substantially all of the content of the thermal treatment unit is removed as a single stream that forms the partially upgraded bitumen product. Alternatively, two separate streams can be removed from the thermal treatment unit, e.g., a liquid phase underflow stream that constitutes the partially upgraded bitumen product (which can also be referred to as a gas-depleted partially upgraded bitumen product), and an overhead vapour phase stream that includes vapours and non-condensable gas components. The partially upgraded bitumen product can then be supplied for pipelining or storage 342.

[353] Optionally, the partially upgraded bitumen product or the gas-depleted partially upgraded bitumen product can be subjected to a separation step 344, which can include separation in a flash column for example, to separate a thermally treated light fraction (including for instance distillate, gasoil and naphtha components), from a thermally treated heavy fraction. It is to be understood that when referring to this separation step, it can include a plurality of separation stages and units. For example, the plurality of separation steps could include a flash column followed by a fractionation column that receives the bottoms of the flash column, and then a vacuum distillation column that receives the bottoms of the fractionation column. Other arrangements of flash vessels, fractionation columns and distillation columns for separating the thermally treated stream into different output streams can also be implemented.

[354] In summary, the series of steps shown in Figure 7 illustrates implementations where characteristics of the deasphalted bitumen upstream of the thermal treatment can be adjusted to attain or maintain given properties of the deasphalted bitumen that is fed to the thermal treatment unit, such that the thermal treatment unit is operated according to a given set of conditions that can remain substantially constant at least for a given period of time. In contrast, in Figure 6, it is the operating conditions of the thermal treatment that can be adjusted to take into account the variability in the properties of the deasphalted bitumen derived from the in situ recovery operation that includes subsurface deasphalting.

[355] Although Figures 6 and 7 are presented as distinct control strategies, it is to be understood that both control strategies can be used and combined to further enhance control options, for instance in circumstances where there may be notable variability. This scenario can be envisioned for instance when the recovery process evolves over time, especially during transition from start-up operations to regular operations, and during transition from regular operations to mature or wind-down operations of the in situ bitumen recovery process.

[356] Referring now to Figure 8, an example implementation of the thermal treatment and downstream processing will be described. The deasphalted bitumen feedstock 454 can be supplied to the thermal treatment unit 456, which can include a pre-heater 458 that can be a direct-fired heater for heating the feedstock to a desired temperature.
The thermal treatment unit 456 can also include a soaker tank 460 that receives the preheated feedstock and maintains the material at desired pressure conditions for a certain treatment time. The soaker tank 460 can be configured depending on the desired temperature and pressure conditions. The soaker tank 460 can be a relatively simple unit that does not include any heaters or the like for inputting additional heat into the feedstock, but rather maintains the general temperature of the material. The soaker tank 460 can be equipped with a heating jacket to insulate the tank and minimize heat loss.

[357] The partially upgraded bitumen product 462 is then withdrawn from the soaker tank 460 and can be supplied to downstream separation vessels. For example, as illustrated in Figure 8, the partially upgraded bitumen product 462 can be fed to a primary separation vessel 464 that can be a flash tank to produce a vapour stream 466 and a liquid stream 468. The vapour stream can include C3 and C4 hydrocarbons that can be used as fuel, for example in the pre-heater 458. The liquid stream 468 includes the heavier hydrocarbons and can be supplied into a secondary separation vessel 470 which can be a fractionation column equipped with a reflux unit 472 and a reboiler 474. The fractionation column can produce various output stream depending on its design. For example, the fractionation column can produce a naphtha overhead stream 476, a gas oil side draw stream 478, and a heavy hydrocarbon bottom stream 480. Alternatively, the fractionation column could have only two output streams: a bottoms and an overhead. The naphtha overhead stream 476 can be used in various applications as diluent.

[358] The heavy hydrocarbon bottom stream 480 can be considered a product stream or can be subjected to further processing depending on its composition. For example, if the feedstock 454 is substantially or fully deasphalted, then the resulting heavy hydrocarbon bottom stream 480 can be handled as a hot bitumen product and can thus be cooled and supplied to storage or can be diluted for pipelining. If the feedstock contains a notable concentration of asphaltenes, then the heavy hydrocarbon bottom stream 480 can be subjected to solvent deasphalting (SDA) 482 to produce a solvent diluted bitumen 484 and a solvent rich asphaltene stream 486, both of which are subjected to solvent recovery to respectively produce a deasphalted oil product 488 and an asphaltene rich residue 490 that can be disposed of or further processed.

[359] Still referring to Figure 8, in some implementations, a hydrogen and/or a transfer agent stream 492 can be added to the bitumen feedstock upstream of the pre-heater 458.
In addition, a recycled oil stream 494 can be added to the feedstock 454 upstream of the pre-heater 458. The recycled oil can be obtained from downstream sources that are part of the overall process, such as from the deasphalted oil product 488 or the heavy hydrocarbon bottom stream 480.

[360] While the thermal treatment and downstream processing systems described in relation to Figure 8 can be used in combination with the in situ deasphalting processes described herein, it is also noted that alternative systems, processes and equipment can also be used. For example, various types of vessel designs can be used for the pre-heater (e.g., direct fired or indirect heat exchanger). In addition, alternatives to the soaker tank can also be used, such as reaction vessels having certain configurations and designs, having integrated heater distributed within the vessel to maintain certain heating characteristics, and the like. Furthermore, downstream separation systems can include various designs for separating the partially upgraded bitumen product 462 into desired hydrocarbon streams for sale or addition into other parts of the process. When the thermal treatment unit is controlled based on the in situ process, it is noted that one or more of the various pieces of equipment can be controlled to obtain the desired outcome.
For example, heating enables by the pre-heater, residence time in the soaker tank, the addition of hydrogen or a transfer agent, and/or the addition of recycled oil could be controlled in response to measured characteristics of the in situ process.

Claims

59

1. A process for producing a partially upgraded bitumen product, the process comprising:
an in situ bitumen recovery operation comprising:
introducing an asphaltene-precipitating solvent into a subsurface formation to contact bitumen contained in the subsurface formation, the bitumen comprising a light fraction and a heavy fraction comprising asphaltenes;
inducing in situ precipitation of at least a portion of the asphaltenes within the subsurface formation to produce a precipitated asphaltene material and a mobilized fluid comprising a deasphalted bitumen fraction;
recovering the mobilized fluid as a production fluid comprising the deasphalted bitumen fraction, water, solids and a portion of the asphaltene-precipitating solvent while leaving a majority of the precipitated asphaltene material within the subsurface formation;
separating deasphalted bitumen from the production fluid;
determining a property of the deasphalted bitumen; and subjecting the deasphalted bitumen to a thermal treatment at about or below incipient coking conditions to produce the partially upgraded bitumen product, wherein the thermal treatment comprises adjusting an operating parameter of the thermal treatment based on the property of the deasphalted bitumen stream.

2. The process of claim 1, wherein all of the precipitated asphaltene material is left within the subsurface formation and the production fluid contains substantially none of the precipitated asphaltene material.

3. The process of claim 1 or 2, wherein introducing the asphaltene-precipitating solvent into the subsurface formation comprises injecting the asphaltene-precipitating solvent Date Recue/Date Received 2021-04-23 via a horizontal injection well provided in the subsurface formation; and wherein the production fluid is recovered via a horizontal production well that is located below the horizontal injection well.

4. The process of any one of claims 1 to 3, wherein the asphaltene-precipitating solvent comprises an alkane solvent.

5. The process of claim 4, wherein the alkane solvent comprises propane, butane, pentane, hexane, heptane or a mixture thereof.

6. The process of claim 5, wherein the alkane solvent comprises propane.

7. The process of claim 5, wherein the alkane solvent comprises butane.

8. The process of claim 5, wherein the alkane solvent comprises pentane.

9. The process of any one of claims 1 to 8, wherein subjecting the deasphalted bitumen to the thermal treatment comprises heating the deasphalted bitumen to a temperature between 200 C and 475 C.

10. The process of any one of claims 1 to 8, wherein subjecting the deasphalted bitumen to the thermal treatment comprises heating the deasphalted bitumen to a temperature between 350 C and 450 C.

11. The process of any one of claims 1 to 10, wherein the thermal treatment is performed for a duration of up to 300 minutes.

12. The process of any one of claims 1 to 10, wherein the thermal treatment is performed for a duration below 60 minutes.

13. The process of any one of claims 1 to 10, wherein the thermal treatment is performed for a duration below 15 minutes.

14. The process of any one of claims 1 to 10, wherein the thermal treatment is performed for a duration between 5 minutes and 60 minutes.
Date Recue/Date Received 2021-04-23

15. The process of any one of claims 1 to 10, wherein the thermal treatment is performed for a duration above 5 minutes.

16. The process of any one of claims 1 to 10, wherein the thermal treatment is performed for a duration of between 15 minutes and 240 minutes.

17. The process of any one of claims 1 to 16, wherein the thermal treatment is performed at a pressure between 50 psig and 1500 psig.

18. The process of any one of claims 1 to 16, wherein the thermal treatment is performed at a pressure between 50 psig and 1000 psig.

19. The process of any one of claims 1 to 18, wherein separating the deasphalted bitumen from the production fluid comprises removing water and solids from the production fluid.

20. The process of any one of claims 1 to 19, wherein separating deasphalted bitumen from the production fluid comprises recovering at least a portion of the asphaltene-precipitating solvent from the production fluid to obtain a recovered asphaltene-precipitating solvent for reintroduction into the subsurface formation.

21. The process of any one of claims 1 to 20, wherein introducing the asphaltene-precipitating solvent into the subsurface formation comprises vaporizing the asphaltene-precipitating solvent and injecting the asphaltene-precipitating solvent into the subsurface formation in vapor phase.

22. The process of any one of claims 1 to 21, wherein conditions of the in situ bitumen recovery operation comprise providing a solvent-to-bitumen ratio of the mobilized fluid that is sufficiently high to cause the in situ precipitation of asphaltenes at operating extraction temperatures and pressures.

23. The process of claim 22, wherein the solvent-to-bitumen ratio of the mobilized fluid is sufficiently high to cause substantially all of the asphaltenes to precipitate such that the deasphalted bitumen fraction is fully deasphalted.
Date Recue/Date Received 2021-04-23

24. The process of claim 22, wherein the solvent-to-bitumen ratio of the mobilized fluid is provided to cause partial precipitation of asphaltenes such that the deasphalted bitumen fraction comprises a reduced asphaltene content.

25. The process of any one of claims 1 to 24, wherein the property of the deasphalted bitumen comprises at least one of asphaltene content of the deasphalted bitumen, a compositional characteristic of the deasphalted bitumen, a viscosity of the deasphalted bitumen and a density of the deasphalted bitumen.

26. The process of any one of claims 1 to 25, further comprising combining the deasphalted bitumen with a second hydrocarbon material to obtain a combined deasphalted bitumen material that is subjected to the thermal treatment.

27. The process of claim 26, wherein combining the deasphalted bitumen with the second hydrocarbon material to obtain the combined deasphalted bitumen material is performed when the property of the deasphalted bitumen is above or below a given threshold.

28. The process of claim 26 or 27, wherein the second hydrocarbon material comprises a second deasphalted bitumen.

29. The process of claim 28, wherein the second deasphalted bitumen is obtained from a second subsurface formation.

30. The process of any one of claims 25 to 29, further comprising subjecting the deasphalted bitumen to an at-surface deasphalting treatment to further reduce the asphaltene content of the deasphalted bitumen prior to the thermal treatment.

31. The process of claim 30, wherein the at-surface deasphalting treatment comprises using at least a portion of the recovered asphaltene-precipitating solvent as deasphalting solvent.

32. The process of any one of claims 26 to 31, wherein the deasphalted bitumen and the second hydrocarbon material are combined in relative proportions so that the combined deasphalted bitumen material has a predetermined composition based on desired operating parameters of the thermal treatment.
Date Recue/Date Received 2021-04-23

33. The process of any one of claims 1 to 25, further comprising combining multiple production fluids respectively obtained from a plurality of in situ recovery wells to form a combined production fluid, and separating the deasphalted bitumen from the combined production fluid.

34. The process of any one of claims 1 to 33, wherein subjecting the deasphalted bitumen to the thermal treatment comprises maintaining the deasphalted bitumen in liquid phase during the thermal treatment.

35. The process of claim 34, wherein maintaining the deasphalted bitumen in liquid phase comprises providing conditions to cause a transfer of hydrogen from the heavy fraction to the light fraction directly in the liquid phase.

36. The process of any one of claims 1 to 35, wherein the thermal treatment comprises supplying the deasphalted bitumen to a thermal treatment vessel and withdrawing the partially upgraded bitumen product from the thermal treatment vessel as a single stream from a product outlet.

37. The process of claim 36, wherein the thermal treatment comprises feeding the single stream of partially upgraded bitumen product to a gas separator and removing at least a portion of a gas phase from the partially upgraded bitumen product.

38. The process of any one of claims 1 to 37, wherein adjusting the operating parameter of the thermal treatment in accordance with the property of the deasphalted bitumen comprises adjusting at least one of temperature, duration and pressure of the thermal treatment.

39. The process of any one of claims 1 to 38, wherein subjecting the deasphalted bitumen to the thermal treatment comprises adding an external source of hydrogen to the deasphalted bitumen.

40. The process of claim 39, wherein the external source of hydrogen is a diatomic hydrogen-containing gas.
Date Recue/Date Received 2021-04-23

41. The process of any one of claims 1 to 40, wherein subjecting the deasphalted bitumen to the thermal treatment comprises adding a hydrogen transfer agent to the deasphalted bitumen.

42. The process of claim 41, wherein the hydrogen transfer agent comprises paraffins, naphthenes, naphtheno-aromatics and/or aromatics.

43. The process of claim 41, wherein the hydrogen transfer agent comprises at least one of butane, propane, methane, tetralin, decalin, and anthracene.

44. The process of claim 41, wherein the hydrogen transfer agent comprises a hydrogen donor.

45. The process of claim 44, wherein the hydrogen donor comprises at least one of tetralin, decalin, synthetic crude oil, fractions of synthetic crude oil, tight oil, shale oil and light crude oils.

46. The process of any one of claims 1 to 45, further comprising diluting the partially upgraded bitumen product with a diluent to obtain a diluted bitumen product.

47. The process of claim 46, wherein the diluent comprises an aromatic diluent, a naphthenic diluent, natural gas condensates, synthetic crude, a fraction of synthetic crude oil or combinations thereof.

48. The process of claim 46 or 47, wherein the diluted bitumen product is diluted to a predetermined pipeline specification, and is also based on the determined property of the partially upgraded bitumen product.

49. The process of any one of claims 1 to 48, further comprising recovering heat from the partially upgraded bitumen product and reusing at least a portion of the recovered heat in the in situ bitumen recovery operation.

50. The process of claim 49, wherein the heat is at least partly reused for pre-heating a process stream that is part of the in situ bitumen recovery operation prior to a unit operation.
Date Recue/Date Received 2021-04-23

51. The process of any one of claims 1 to 50, wherein the deasphalted bitumen has a variable composition over time.

52. The process of claim 51, wherein the deasphalted bitumen has a higher asphaltene content during an earlier stage of the in situ bitumen recovery operation, and a lower asphaltene content during a later stage of the in situ bitumen recovery operation.

53. The process of claim 52, wherein the earlier stage comprises a startup stage, and the later stage comprises a normal operation stage of the in situ bitumen recovery operation.

54. The process of any one of claims 51 to 53, further comprising controlling the in situ bitumen recovery operation or the thermal treatment or a combination thereof, based on the variable composition of the deasphalted bitumen.

55. The process of claim 54, wherein the thermal treatment is operated at lower severity conditions when the deasphalted bitumen has a higher asphaltene content, and is operated at higher severity conditions when the deasphalted bitumen has a lower asphaltene content.

56. The process of claim 55, wherein the thermal treatment is continuously controlled based on the variable composition of the deasphalted bitumen.

57. The process of claim 55, wherein the thermal treatment is intermittently controlled based on the variable composition of the deasphalted bitumen.

58. A process for producing a partially upgraded bitumen product, the process comprising:
recovering a mobilized subsurface fluid as production fluid comprising a deasphalted bitumen fraction as part of an in situ bitumen recovery operation, comprising:
introducing an asphaltene-precipitating solvent into a subsurface formation to contact bitumen contained in the subsurface formation, the bitumen comprising a light fraction and a heavy fraction comprising asphaltenes;
Date Recue/Date Received 2021-04-23 inducing in situ precipitation of at least a portion of the asphaltenes within the subsurface formation to produce a precipitated asphaltene material and the mobilized subsurface fluid comprising the deasphalted bitumen fraction; and producing the mobilized subsurface fluid to the surface as the production fluid that includes the deasphalted bitumen fraction, water, solids and a portion of the asphaltene-precipitating solvent while leaving a majority of the precipitated asphaltene material within the subsurface formation;
separating deasphalted bitumen from the production fluid;
determining a property of the deasphalted bitumen;
adjusting a variable related to the in situ bitumen recovery operation based on the property of the deasphalted bitumen to obtain a deasphalted bitumen feedstock; and subjecting the deasphalted bitumen feedstock to a thermal treatment at about or below incipient coking conditions to produce the partially upgraded bitumen product.

59. The process of claim 58, wherein all of the precipitated asphaltene material is left within the subsurface formation and the production fluid contains substantially none of the precipitated asphaltene material.

60. The process of claim 58 or 59, wherein introducing the asphaltene-precipitating solvent into the subsurface formation comprises injecting the asphaltene-precipitating solvent via a horizontal injection well provided in the subsurface formation;
and wherein the production fluid is recovered via a horizontal production well that is located below the horizontal injection well.

61. The process of any one of claims 58 to 60, wherein the asphaltene-precipitating solvent comprises an alkane solvent.
Date Recue/Date Received 2021-04-23

62. The process of claim 61, wherein the alkane solvent comprises propane, butane, pentane, hexane, heptane or a mixture thereof.

63. The process of claim 61, wherein the alkane solvent comprises propane.

64. The process of claim 61, wherein the alkane solvent comprises butane.

65. The process of claim 61, wherein the alkane solvent comprises pentane.

66. The process of any one of claims 58 to 65, wherein subjecting the deasphalted bitumen to the thermal treatment comprises heating the deasphalted bitumen to a temperature between 200 C and 475 C.

67. The process of any one of claims 58 to 65, wherein subjecting the deasphalted bitumen to the thermal treatment comprises heating the deasphalted bitumen to a temperature between 350 C and 450 C.

68. The process of any one of claims 58 to 67, wherein the thermal treatment is performed for a duration of up to 300 minutes.

69. The process of any one of claims 58 to 67, wherein the thermal treatment is performed for a duration below 60 minutes.

70. The process of any one of claims 58 to 67, wherein the thermal treatment is performed for a duration below 15 minutes.

71. The process of any one of claims 58 to 67, wherein the thermal treatment is performed for a duration between 5 minutes and 60 minutes.

72. The process of any one of claims 58 to 67, wherein the thermal treatment is performed for a duration above 5 minutes.

73. The process of any one of claims 58 to 67, wherein the thermal treatment is performed for a duration of between 15 minutes and 240 minutes.

74. The process of any one of claims 58 to 73, wherein the thermal treatment is performed at a pressure between 50 psig and 1500 psig.
Date Recue/Date Received 2021-04-23

75. The process of any one of claims 58 to 73, wherein the thermal treatment is performed at a pressure between 50 psig and 1000 psig.

76. The process of any one of claims 58 to 75, wherein separating deasphalted bitumen from the production fluid comprises removing water and solids from the production fluid.

77. The process of any one of claims 58 to 76, wherein separating deasphalted bitumen from the production fluid comprises recovering at least a portion of the asphaltene-precipitating solvent from the production fluid to obtain a recovered asphaltene-precipitating solvent for reintroduction into the subsurface formation.

78. The process of any one of claims 58 to 77, wherein introducing the asphaltene-precipitating solvent into the subsurface formation comprises vaporizing the asphaltene-precipitating solvent at surface, and injecting the asphaltene-precipitating solvent into the subsurface formation in vapor phase.

79. The process of any one of claims 58 to 78, wherein conditions of the in situ bitumen recovery operation comprise providing a solvent-to-bitumen ratio of the mobilized fluid that is sufficiently high to cause the in situ precipitation of asphaltenes at operating extraction temperatures and pressures.

80. The process of claim 79, wherein the solvent-to-bitumen ratio of the mobilized fluid is sufficiently high to cause substantially all of the asphaltenes to precipitate such that the deasphalted bitumen fraction is fully deasphalted.

81. The process of claim 79, wherein the solvent-to-bitumen ratio of the mobilized fluid is provided to cause partial precipitation of asphaltenes such that the deasphalted bitumen fraction comprises a reduced asphaltene content.

82. The process of any one of claims 58 to 81, wherein adjusting the variable related to the in situ bitumen recovery operation comprises adjusting at least one operating parameter related thereto.

83. The process of claim 82, wherein adjusting the operating parameter of the in situ bitumen recovery operation comprises at least one of modifying the type or Date Recue/Date Received 2021-04-23 composition of the asphaltene-precipitating solvent introduced into the subsurface formation, modifying an amount or rate of the asphaltene-precipitating solvent introduced into the subsurface formation, adjusting a solvent-to-bitumen ratio within the subsurface formation or of the production fluid, adjusting a temperature of the asphaltene-precipitating solvent to be introduced in the subsurface formation, adjusting a temperature within the subsurface formation, and adjusting heat that is provided to the reservoir.

84. The process of any one of claims 58 to 83, wherein adjusting the variable related to the in situ bitumen recovery operation comprises adjusting at least one characteristic of the deasphalted bitumen.

85. The process of any one of claims 58 to 84, wherein the property of the deasphalted bitumen comprises at least one of asphaltene content of the deasphalted bitumen, a compositional characteristic of the deasphalted bitumen, a viscosity of the deasphalted bitumen and a density of the deasphalted bitumen.

86. The process of any one of claims 58 to 85, further comprising combining the deasphalted bitumen with a second hydrocarbon material to obtain a combined deasphalted bitumen material that is subjected to the thermal treatment.

87. The process of claim 86, wherein combining the deasphalted bitumen with the second hydrocarbon material to obtain the combined deasphalted bitumen material is performed when the property of the deasphalted bitumen is above or below a given threshold.

88. The process of claim 86 or 87, wherein the second hydrocarbon material comprises a second deasphalted bitumen.

89. The process of claim 88, wherein the second deasphalted bitumen is obtained from a second subsurface formation.

90. The process of any one of claims 86 to 89, further comprising subjecting the deasphalted bitumen to an at-surface deasphalting treatment to further reduce the asphaltene content of the deasphalted bitumen prior to the thermal treatment.
Date Recue/Date Received 2021-04-23

91. The process of claim 90, wherein the at-surface deasphalting treatment comprises using at least a portion of the recovered asphaltene-precipitating solvent as deasphalting solvent.

92. The process of any one of claims 86 to 91, wherein the deasphalted bitumen and the second hydrocarbon material are combined in relative proportions so that the combined deasphalted bitumen material has a predetermined composition based on desired operating parameters of the thermal treatment.

93. The process of any one of claims 58 to 91, further comprising combining multiple production fluids respectively obtained from a plurality of in situ recovery wells to form a combined production fluid, and separating the deasphalted bitumen from the combined production fluid.

94. The process of any one of claims 58 to 93, wherein subjecting the deasphalted bitumen to the thermal treatment comprises maintaining the deasphalted bitumen in liquid phase during the thermal treatment.

95. The process of claim 94, wherein maintaining the deasphalted bitumen in liquid phase comprises providing conditions to cause a transfer of hydrogen from the heavy fraction to the light fraction directly in the liquid phase.

96. The process of any one of claims 58 to 95, wherein the thermal treatment comprises supplying the deasphalted bitumen to a thermal treatment vessel and withdrawing the partially upgraded bitumen product from the thermal treatment vessel as a single stream from a product outlet.

97. The process of claim 96, wherein the thermal treatment comprises feeding the single stream of partially upgraded bitumen product to a gas separator and removing at least a portion of a gas phase from the partially upgraded bitumen product.

98. The process of any one of claims 58 to 97, wherein subjecting the deasphalted bitumen to the thermal treatment comprises adding an external source of hydrogen to the deasphalted bitumen.
Date Recue/Date Received 2021-04-23

99. The process of claim 98, wherein the external source of hydrogen is a diatomic hydrogen-containing gas.

100. The process of any one of claims 58 to 99, wherein subjecting the deasphalted bitumen to the thermal treatment comprises adding a hydrogen transfer agent to the deasphalted bitumen.

101. The process of claim 100, wherein the hydrogen transfer agent comprises paraffins, naphthenes, naphtheno-aromatics and/or aromatics.

102. The process of claim 100, wherein the hydrogen transfer agent comprises at least one of butane, propane, methane, tetralin, decalin, and anthracene.

103. The process of claims 100, wherein the hydrogen transfer agent comprises a hydrogen donor.

104. The process of claim 103, wherein the hydrogen donor comprises at least one of tetralin, decalin, synthetic crude oil, fractions of synthetic crude oil, tight oil, shale oil and light crude oils.

105. The process of any one of claims 58 to 104, further comprising diluting the partially upgraded bitumen product with a diluent to obtain a diluted bitumen product.

106. The process of claim 105, wherein the diluent comprises an aromatic diluent, a naphthenic diluent, natural gas condensates, synthetic crude, a fraction of synthetic crude oil or streams thereof.

107. The process of claim 105 or 106, wherein the diluted bitumen product is diluted to a predetermined pipeline specification.

108. The process of any one of claims 58 to 107, further comprising recovering heat from the partially upgraded bitumen product and reusing at least a portion of the recovered heat in the in situ bitumen recovery operation.

109. The process of claim 108, wherein the heat is at least partly reused for pre-heating a process stream that is part of the in situ bitumen recovery operation prior to a unit operation.
Date Recue/Date Received 2021-04-23

110. The process of any one of claims 58 to 109, wherein the deasphalted bitumen has a variable composition over time.

111. The process of claim 110, wherein the deasphalted bitumen has a higher asphaltene content during an earlier stage of the in situ bitumen recovery operation, and a lower asphaltene content during a later stage of the in situ bitumen recovery operation.

112. The process of claim 111, wherein the earlier stage comprises a startup stage, and the later stage comprises a normal operation stage of the in situ bitumen recovery operation.

113. The process of any one of claims 110 to 112, further comprising controlling the in situ bitumen recovery operation or the thermal treatment or a combination thereof, based on the variable composition of the deasphalted bitumen.

114. The process of claim 113, wherein the thermal treatment is operated at lower severity conditions when the deasphalted bitumen has a higher asphaltene content, and is operated at higher severity conditions when the deasphalted bitumen has a lower asphaltene content.

115. The process of claim 114, wherein the thermal treatment is continuously controlled based on the variable composition of the deasphalted bitumen.

116. The process of claim 114, wherein the thermal treatment is intermittently controlled based on the variable composition of the deasphalted bitumen.

117. A process for producing a partially upgraded bitumen product, the process comprising:
an in situ bitumen recovery operation comprising:
introducing an asphaltene-precipitating solvent into a subsurface formation to contact bitumen contained in the subsurface formation, the bitumen comprising a light fraction and a heavy fraction comprising asphaltenes;
Date Recue/Date Received 2021-04-23 inducing in situ precipitation of at least a portion of the asphaltenes within the subsurface formation to produce a precipitated asphaltene material and a mobilized fluid comprising a deasphalted bitumen fraction;
recovering the mobilized fluid as a production fluid comprising the deasphalted bitumen fraction, water, solids and a portion of the asphaltene-precipitating solvent while leaving a majority of the precipitated asphaltene material within the subsurface formation;
separating deasphalted bitumen from the production fluid;
subjecting the deasphalted bitumen to a thermal treatment at about or below incipient coking conditions to produce the partially upgraded bitumen product;
determining a property of the partially upgraded bitumen product; and adjusting an operating parameter of the thermal treatment based on the determined property of the partially upgraded bitumen product.

118. The process of claim 117, wherein all of the precipitated asphaltene material is left within the subsurface formation and the production fluid contains substantially none of the precipitated asphaltene material.

119. The process of claim 117 or 118, wherein introducing the asphaltene-precipitating solvent into the subsurface formation comprises injecting the asphaltene-precipitating solvent via a horizontal injection well provided in the subsurface formation;
and wherein the production fluid is recovered via a horizontal production well that is located below the horizontal injection well.

120. The process of any one of claims 117 to 119, wherein the asphaltene-precipitating solvent comprises an alkane solvent.

121. The process of claim 120, wherein the alkane solvent comprises propane, butane, pentane, hexane, heptane or a mixture thereof.

122. The process of claim 121, wherein the alkane solvent comprises propane.
Date Recue/Date Received 2021-04-23

123. The process of claim 122, wherein the alkane solvent comprises butane.

124. The process of claim 122, wherein the alkane solvent comprises pentane.

125. The process of any one of claims 117 to 124, wherein subjecting the deasphalted bitumen to the thermal treatment comprises heating the deasphalted bitumen to a temperature between 200 C and 475 C.

126. The process of any one of claims 117 to 124, wherein subjecting the deasphalted bitumen to the thermal treatment comprises heating the deasphalted bitumen to a temperature between 350 C and 450 C.

127. The process of any one of claims 117 to 126, wherein the thermal treatment is performed for a duration of up to 300 minutes.

128. The process of any one of claims 117 to 126, wherein the thermal treatment is performed for a duration below 60 minutes.

129. The process of any one of claims 117 to 126, wherein the thermal treatment is performed for a duration below 15 minutes.

130. The process of any one of claims 117 to 126, wherein the thermal treatment is performed for a duration between 5 minutes and 60 minutes.

131. The process of any one of claims 117 to 126, wherein the thermal treatment is performed for a duration above 5 minutes.

132. The process of any one of claims 117 to 126, wherein the thermal treatment is performed for a duration of between 15 minutes and 240 minutes.

133. The process of any one of claims 117 to 132, wherein the thermal treatment is performed at a pressure between 50 psig and 1500 psig.

134. The process of any one of claims 117 to 132, wherein the thermal treatment is performed at a pressure between 50 psig and 1000 psig.
Date Recue/Date Received 2021-04-23

135. The process of any one of claims 117 to 134, wherein separating the deasphalted bitumen from the production fluid comprises removing water and solids from the production fluid.

136. The process of any one of claims 117 to 135, wherein separating the deasphalted bitumen from the production fluid comprises recovering at least a portion of the asphaltene-precipitating solvent from the production fluid to obtain a recovered asphaltene-precipitating solvent for reintroduction into the subsurface formation.

137. The process of any one of claims 117 to 136, wherein introducing the asphaltene-precipitating solvent into the subsurface formation comprises vaporizing the asphaltene-precipitating solvent at surface, and injecting the asphaltene-precipitating solvent into the subsurface formation in vapor phase.

138. The process of any one of claims 117 to 137, wherein conditions of the in situ bitumen recovery operation comprise providing a solvent-to-bitumen ratio of the mobilized fluid that is sufficiently high to cause the in situ precipitation of asphaltenes at operating extraction temperatures and pressures.

139. The process of claim 138, wherein the solvent-to-bitumen ratio of the mobilized fluid is sufficiently high to cause substantially all of the asphaltenes to precipitate such that the deasphalted bitumen fraction is fully deasphalted.

140. The process of claim 138, wherein the solvent-to-bitumen ratio of the mobilized fluid is provided to cause partial precipitation of asphaltenes such that the deasphalted bitumen fraction comprises a reduced asphaltene content.

141. The process of any one of claims 117 to 140, wherein the determined property of the partially upgraded bitumen product comprises at least one of asphaltene content of the partially upgraded bitumen product, a compositional characteristic of the partially upgraded bitumen product, a viscosity of the partially upgraded bitumen product, a density of the partially upgraded bitumen product, and an olefin content of the partially upgraded bitumen product.
Date Recue/Date Received 2021-04-23

142. The process of any one of claims 117 to 141, further comprising combining the deasphalted bitumen with a second hydrocarbon material to obtain a combined deasphalted bitumen material that is subjected to the thermal treatment.

143. The process of claim 142, wherein combining the deasphalted bitumen with the second hydrocarbon material to obtain the combined deasphalted bitumen material is performed when the property of the deasphalted bitumen is above or below a given threshold.

144. The process of claim 142 or 143, wherein the second hydrocarbon material comprises a second deasphalted bitumen.

145. The process of claim 144, wherein the second deasphalted bitumen is obtained from a second subsurface formation.

146. The process of any one of claims 141 to 145, further comprising subjecting the deasphalted bitumen to an at-surface deasphalting treatment to further reduce an asphaltene content of the deasphalted bitumen prior to the thermal treatment.

147. The process of claim 146, wherein the at-surface deasphalting treatment comprises using at least a portion of the recovered asphaltene-precipitating solvent as deasphalting solvent.

148. The process of any one of claims 142 to 147, wherein the deasphalted bitumen and the second hydrocarbon material are combined in relative proportions so that the combined deasphalted bitumen material has a predetermined composition based on desired operating parameters of the thermal treatment.

149. The process of any one of claims 117 to 141, further comprising combining multiple production fluids respectively obtained from a plurality of in situ recovery wells to form a combined production fluid, and separating the deasphalted bitumen from the combined production fluid.

150. The process of any one of claims 117 to 149, wherein subjecting the deasphalted bitumen to the thermal treatment comprises maintaining the deasphalted bitumen in liquid phase during the thermal treatment.
Date Recue/Date Received 2021-04-23

151. The process of claim 150, wherein maintaining the deasphalted bitumen in liquid phase comprises providing conditions to cause a transfer of hydrogen from the heavy fraction to the light fraction directly in the liquid phase.

152. The process of any one of claims 117 to 151, wherein the thermal treatment comprises supplying the deasphalted bitumen to a thermal treatment vessel and withdrawing the partially upgraded bitumen product from the thermal treatment vessel as a single stream from a product outlet.

153. The process of claim 152, wherein the thermal treatment comprises feeding the single stream of partially upgraded bitumen product to a gas separator and removing at least a portion of a gas phase from the partially upgraded bitumen product.

154. The process of any one of claims 134 to 153, wherein adjusting the operating parameter of the thermal treatment based on the determined property of the partially upgraded bitumen product comprises adjusting at least one of the temperature, the duration and the pressure of the thermal treatment.

155. The process of any one of claims 117 to 154, wherein subjecting the deasphalted bitumen to the thermal treatment comprises adding an external source of hydrogen to the deasphalted bitumen.

156. The process of claim 155, wherein the external source of hydrogen is a diatomic hydrogen-containing gas.

157. The process of any one of claims 117 to 156, wherein subjecting the deasphalted bitumen to the thermal treatment comprises adding a hydrogen transfer agent to the deasphalted bitumen.

158. The process of claim 157, wherein the hydrogen transfer agent comprises paraffins, naphthenes, naphtheno-aromatics and/or aromatics.

159. The process of claim 157, wherein the hydrogen transfer agent comprises at least one of butane, propane, methane, tetralin, decalin, and anthracene.
Date Recue/Date Received 2021-04-23

160. The process of claims 157, wherein the hydrogen transfer agent comprises a hydrogen donor.

161. The process of claim 160, wherein the hydrogen donor comprises at least one of tetralin, decalin, synthetic crude oil, fractions of synthetic crude oil, tight oil, shale oil and light crude oils.

162. The process of any one of claims 117 to 161, further comprising diluting the partially upgraded bitumen product with a diluent to obtain a diluted bitumen product.

163. The process of claim 162, wherein the diluent comprises an aromatic diluent, a naphthenic diluent, natural gas condensates, synthetic crude, a fraction of synthetic crude oil or streams thereof.

164. The process of claim 162 or 163, wherein the diluted bitumen product is diluted to a predetermined pipeline specification, and is also based on the determined property of the partially upgraded bitumen product.

165. The process of any one of claims 117 to 164, further comprising recovering heat from the partially upgraded bitumen product and reusing at least a portion of the recovered heat in the in situ bitumen recovery operation.

166. The process of claim 165, wherein the heat is at least partly reused for pre-heating a process stream that is part of the in situ bitumen recovery operation prior to a unit operation.

167. The process of any one of claims 117 to 166, wherein the deasphalted bitumen has a variable composition over time.

168. The process of claim 167, wherein the deasphalted bitumen has a higher asphaltene content during an earlier stage of the in situ bitumen recovery operation, and a lower asphaltene content during a later stage of the in situ bitumen recovery operation.

169. The process of claim 168, wherein the earlier stage comprises a startup stage, and the later stage comprises a normal operation stage of the in situ bitumen recovery operation.
Date Recue/Date Received 2021-04-23

170. The process of any one of claims 167 to 169, further comprising controlling the in situ bitumen recovery operation or the thermal treatment or a combination thereof, based on the variable composition of the deasphalted bitumen.

171. The process of claim 170, wherein the thermal treatment is operated at lower severity conditions when the deasphalted bitumen has a higher asphaltene content, and is operated at higher severity conditions when the deasphalted bitumen has a lower asphaltene content.

172. The process of claim 171, wherein the thermal treatment is continuously controlled based on the variable composition of the deasphalted bitumen.

173. The process of claim 171, wherein the thermal treatment is intermittently controlled based on the variable composition of the deasphalted bitumen.

174. A process for producing a partially upgraded bitumen product, the process comprising:
conducting an in situ bitumen recovery operation, comprising:
introducing an asphaltene-precipitating solvent into a subsurface formation to contact bitumen contained in the subsurface formation, the bitumen comprising a light fraction and a heavy fraction comprising asphaltenes, at conditions to cause in situ precipitation of at least a portion of the asphaltenes within the subsurface formation to produce a precipitated asphaltene material and a mobilized fluid comprising a deasphalted bitumen fraction;
recovering the mobilized fluid as a production fluid comprising the deasphalted bitumen fraction, water, solids and a portion of the asphaltene-precipitating solvent while leaving a majority of the precipitated asphaltene material within the subsurface formation; and separating deasphalted bitumen from the production fluid; and Date Recue/Date Received 2021-04-23 subjecting the deasphalted bitumen to a thermal treatment at about or below incipient coking conditions to produce the partially upgraded bitumen product.

175. The process of claim 174, further comprising determining at least one property of the deasphalted bitumen and/or at least one property of the partially upgraded bitumen product, and adjusting at least one operating parameter of the thermal treatment and/or or the in situ bitumen recovery operation based on the at least one determined property.

176. The process of claim 174 or 175, wherein all of the precipitated asphaltene material is left within the subsurface formation and the production fluid contains substantially none of the precipitated asphaltene material.

177. The process of any one of claims 174 to 176, wherein introducing the asphaltene-precipitating solvent into the subsurface formation comprises injecting the asphaltene-precipitating solvent via a horizontal injection well provided in the subsurface formation; and wherein the production fluid is recovered via a horizontal production well that is located below the horizontal injection well.

178. The process of claim 177, wherein horizontal production well and the horizontal injection well are operated according to gravity dominated recovery.

179. The process of any one of claims 174 to 178, wherein the asphaltene-precipitating solvent comprises an alkane solvent.

180. The process of claim 179, wherein the alkane solvent comprises propane, butane, pentane, hexane, heptane or a mixture thereof.

181. The process of claim 180, wherein the alkane solvent comprises propane.

182. The process of claim 180, wherein the alkane solvent comprises butane.

183. The process of claim 180, wherein the alkane solvent comprises pentane.

184. The process of any one of claims 174 to 183, wherein the thermal treatment is operated at a temperature above 200 C.
Date Recue/Date Received 2021-04-23

185. The process of any one of claims 174 to 183, wherein the thermal treatment is operated at a temperature above 250 C.

186. The process of any one of claims 174 to 183, wherein the thermal treatment is operated at a temperature above 300 C.

187. The process of any one of claims 174 to 183, wherein the thermal treatment is operated at a temperature above 350 C.

188. The process of any one of claims 174 to 183, wherein the thermal treatment is operated at a temperature above 400 C.

189. The process of any one of claims 174 to 183, wherein the thermal treatment is operated at a temperature above 450 C.

190. The process of any one of claims 174 to 183, wherein the thermal treatment is operated at a temperature between 350 C and 450 C.

191. The process of any one of claims 174 to 190, wherein the thermal treatment is operated at a residence time of up to 300 minutes.

192. The process of any one of claims 174 to 190, wherein the thermal treatment is operated at a residence time below 60 minutes.

193. The process of any one of claims 174 to 190, wherein the thermal treatment is operated at a residence time below 15 minutes.

194. The process of any one of claims 174 to 190, wherein the thermal treatment is operated at a residence time between 5 minutes and 60 minutes.

195. The process of any one of claims 174 to 190, wherein the thermal treatment is operated at a residence time above 5 minutes.

196. The process of claim 191, wherein the residence time of the thermal treatment is above 15 minutes.
Date Recue/Date Received 2021-04-23

197. The process of claim 191, wherein the residence time of the thermal treatment is above 60 minutes.

198. The process of claim 191, wherein the residence time of the thermal treatment is above 90 minutes.

199. The process of claim 191, wherein the residence time of the thermal treatment is above 150 minutes.

200. The process of claim 191, wherein the residence time of the thermal treatment is above 180 minutes.

201. The process of claim 191, wherein the residence time of the thermal treatment is above 210 minutes.

202. The process of any one of claims 174 to 201, wherein the thermal treatment is operated at a pressure between 50 psig and 1500 psig.

203. The process of any one of claims 174 to 201, wherein the thermal treatment is operated at a pressure between 50 psig and 1000 psig.

204. The process of any one of claims 174 to 203, wherein separating the deasphalted bitumen from the production fluid comprises removing water and solids from the production fluid.

205. The process of any one of claims 174 to 204, wherein separating the deasphalted bitumen from the production fluid comprises recovering at least a portion of the asphaltene-precipitating solvent from the production fluid to obtain a recovered asphaltene-precipitating solvent for reintroduction into the subsurface formation.

206. The process of any one of claims 174 to 205, wherein introducing the asphaltene-precipitating solvent into the subsurface formation comprises vaporizing the asphaltene-precipitating solvent at surface, and injecting the asphaltene-precipitating solvent into the subsurface formation in vapor phase.

207. The process of any one of claims 174 to 206, wherein conditions of the in situ bitumen recovery operation comprise providing a solvent-to-bitumen ratio of the mobilized fluid Date Recue/Date Received 2021-04-23 that is sufficiently high to cause the in situ precipitation of asphaltenes at operating extraction temperatures and pressures.

208. The process of claim 207, wherein the solvent-to-bitumen ratio of the mobilized fluid is sufficiently high to cause substantially all of the asphaltenes to precipitate such that the deasphalted bitumen fraction is fully deasphalted.

209. The process of claim 207, wherein the solvent-to-bitumen ratio of the mobilized fluid is provided to cause partial precipitation of asphaltenes such that the deasphalted bitumen fraction comprises a reduced asphaltene content.

210. The process of any one of claims 174 to 209, further comprising combining the deasphalted bitumen with a second hydrocarbon material to obtain a combined deasphalted bitumen material that is subjected to the thermal treatment.

211. The process of claim 210, wherein the second hydrocarbon material comprises a second deasphalted bitumen.

212. The process of claim 210 or 211, wherein the second deasphalted bitumen is obtained from a second subsurface formation.

213. The process of any one of claims 210 to 212, wherein the deasphalted bitumen and the second hydrocarbon material are combined in relative proportions so that the combined deasphalted bitumen material has a predetermined composition based on desired operating parameters of the thermal treatment.

214. The process of any one of claims 174 to 209, further comprising combining multiple production fluids respectively obtained from a plurality of in situ recovery wells to form a combined production fluid, and separating the deasphalted bitumen from the combined production fluid.

215. The process of any one of claims 174 to 214, wherein subjecting the deasphalted bitumen to the thermal treatment comprises maintaining the deasphalted bitumen in liquid phase during the thermal treatment.
Date Recue/Date Received 2021-04-23

216. The process of claim 215, wherein maintaining the deasphalted bitumen in liquid phase comprises providing conditions to cause a transfer of hydrogen from the heavy fraction to the light fraction directly in the liquid phase.

217. The process of any one of claims 174 to 216, wherein the thermal treatment comprises supplying the deasphalted bitumen to a thermal treatment vessel and withdrawing the partially upgraded bitumen product from the thermal treatment vessel as a single stream from a product outlet.

218. The process of claim 217, wherein the thermal treatment comprises feeding the single stream of partially upgraded bitumen product to a gas separator and removing at least a portion of a gas phase from the partially upgraded bitumen product.

219. The process of any one of claims 174 to 218, wherein subjecting the deasphalted bitumen to the thermal treatment comprises adding an external source of hydrogen to the deasphalted bitumen.

220. The process of claim 219, wherein the external source of hydrogen is a diatomic hydrogen-containing gas.

221. The process of any one of claims 174 to 220, wherein subjecting the deasphalted bitumen to the thermal treatment comprises adding a hydrogen transfer agent to the deasphalted bitumen.

222. The process of claim 221, wherein the hydrogen transfer agent comprises paraffins, naphthenes, naphtheno-aromatics and/or aromatics.

223. The process of claim 221, wherein the hydrogen transfer agent comprises at least one of butane, propane, methane, tetralin, decalin, and anthracene.

224. The process of claims 221, wherein the hydrogen transfer agent comprises a hydrogen donor.

225. The process of claim 224, wherein the hydrogen donor comprises at least one of tetralin, decalin, synthetic crude oil, fractions of synthetic crude oil, tight oil, shale oil and light crude oils.
Date Recue/Date Received 2021-04-23

226. The process of any one of claims 174 to 225, further comprising diluting the partially upgraded bitumen product with a diluent to obtain a diluted bitumen product.

227. The process of claim 226, wherein the diluent comprises an aromatic diluent, a naphthenic diluent, natural gas condensates, synthetic crude, a fraction of synthetic crude oil or streams thereof.

228. The process of claim 226 or 227, wherein the diluted bitumen product is diluted to a predetermined pipeline specification, and is also based on the determined property of the partially upgraded bitumen product.

229. The process of any one of claims 174 to 228, further comprising recovering heat from the partially upgraded bitumen product and reusing at least a portion of the recovered heat in the in situ bitumen recovery operation.

230. The process of claim 229, wherein the heat is at least partly reused for pre-heating a process stream that is part of the in situ bitumen recovery operation prior to a unit operation.

231. The process of any one of claims 174 to 230, wherein the deasphalted bitumen has a variable composition over time.

232. The process of claim 231, wherein the deasphalted bitumen has a higher asphaltene content during an earlier stage of the in situ bitumen recovery operation, and a lower asphaltene content during a later stage of the in situ bitumen recovery operation.

233. The process of claim 232, wherein the earlier stage comprises a startup stage, and the later stage comprises a normal operation stage of the in situ bitumen recovery operation.

234. The process of any one of claims 223 to 233, further comprising controlling the in situ bitumen recovery operation or the thermal treatment or a combination thereof, based on the variable composition of the deasphalted bitumen.

235. The process of claim 234, wherein the thermal treatment is operated at lower severity conditions when the deasphalted bitumen has a higher asphaltene content, and is Date Recue/Date Received 2021-04-23 operated at higher severity conditions when the deasphalted bitumen has a lower asphaltene content.

236. The process of claim 235, wherein the thermal treatment is continuously controlled based on the variable composition of the deasphalted bitumen.

237. The process of claim 235, wherein the thermal treatment is intermittently controlled based on the variable composition of the deasphalted bitumen.

238. A system for producing a partially upgraded bitumen product, the system comprising:
an in situ bitumen recovery facility, comprising:
a horizontal injection well located in a subsurface formation and configured for injecting an asphaltene-precipitating solvent into the subsurface formation to contact bitumen contained therein at conditions to cause in situ precipitation of at least a portion of asphaltenes within the subsurface formation to produce a precipitated asphaltene material and a mobilized fluid comprising a deasphalted bitumen fraction;
a horizontal production well located in the subsurface formation below the horizontal injection well, thereby forming a well pair, the horizontal production well being configured to recover the mobilized fluid to surface as a production fluid that comprises the deasphalted bitumen fraction, water, solids and a portion of the asphaltene-precipitating solvent while leaving a majority of the precipitated asphaltene material within the subsurface formation; and a surface separation unit in fluid communication with the horizontal production well and configured to separate deasphalted bitumen from the production fluid; and a thermal treatment facility in fluid communication with the in situ bitumen recovery facility, and configured to subject the deasphalted bitumen to thermal treatment at about or below incipient coking conditions to produce the partially upgraded bitumen product.
Date Recue/Date Received 2021-04-23

239. The system of claim 238, further comprising a measurement unit configured to determine at least one property of the deasphalted bitumen and/or at least one property of the partially upgraded bitumen product, and a control unit configured to receive information from the measurement unit and to adjust at least one operating parameter of the thermal treatment facility and/or or the in situ bitumen recovery facility based on the at least one determined property.

240. The system of claim 238 or 239, wherein the horizontal production well and the horizontal injection well are configured as a well pair for gravity dominated recovery.

241. The system of any one of claims 238 to 240, wherein the asphaltene-precipitating solvent comprises an alkane solvent.

242. The system of claim 241, wherein the alkane solvent comprises propane, butane, pentane, hexane, heptane or a mixture thereof.

243. The system of claim 242, wherein the alkane solvent comprises propane.

244. The system of claim 242, wherein the alkane solvent comprises butane.

245. The system of claim 242, wherein the alkane solvent comprises pentane.

246. The system of any one of claims 238 to 245, wherein the thermal treatment facility comprises a thermal treatment vessel configured to receive and thermally treat the deasphalted bitumen.

247. The system of claim 246, wherein the thermal treatment vessel is configured to operate at a temperature above 200 C.

248. The system of claim 246, wherein the thermal treatment vessel is configured to operate at a temperature above 250 C.

249. The system of claim 246, wherein the thermal treatment vessel is configured to operate at a temperature above 300 C.

250. The system of claim 246, wherein the thermal treatment vessel is configured to operate at a temperature above 350 C.
Date Recue/Date Received 2021-04-23

251. The system of claim 246, wherein the thermal treatment vessel is configured to operate at a temperature above 400 C.

252. The system of claim 246, wherein the thermal treatment vessel is configured to operate at a temperature above 450 C.

253. The system of claim 246, wherein the thermal treatment vessel is configured to operate at a temperature between 350 C and 450 C.

254. The system of any one of claims 238 to 253, wherein the thermal treatment vessel is configured to operate at a residence time of up to 300 minutes.

255. The system of any one of claims 238 to 253, wherein the thermal treatment vessel is configured to operate at a residence time below 60 minutes.

256. The system of any one of claims 238 to 253, wherein the thermal treatment vessel is configured to operate at a residence time below 15 minutes.

257. The system of any one of claims 238 to 253, wherein the thermal treatment vessel is configured to operate at a residence time between 5 minutes and 60 minutes.

258. The system of any one of claims 238 to 253, wherein the thermal treatment vessel is configured to operate at a residence time above 5 minutes.

259. The system of claim 254, wherein the residence time of the thermal treatment vessel is above 15 minutes.

260. The system of claim 254, wherein the residence time of the thermal treatment vessel is above 60 minutes.

261. The system of claim 254, wherein the residence time of the thermal treatment vessel is above 90 minutes.

262. The system of claim 254, wherein the residence time of the thermal treatment vessel is above 150 minutes.
Date Recue/Date Received 2021-04-23

263. The system of claim 254, wherein the residence time of the thermal treatment vessel is above 180 minutes.

264. The system of claim 254, wherein the residence time of the thermal treatment vessel is above 210 minutes.

265. The system of any one of claims 238 to 264, wherein the thermal treatment vessel is configured to operate at a pressure between 50 psig and 1500 psig.

266. The system of any one of claims 238 to 264, wherein the thermal treatment vessel is configured to operate at a pressure between 50 psig and 1000 psig.

267. The system of any one of claims 238 to 266, wherein the surface separation unit is further configured to separate water and solids from the production fluid.

268. The system of any one of claims 238 to 267, wherein the surface separation unit is further configured to recover at least a portion of the asphaltene-precipitating solvent from the production fluid to obtain a recovered asphaltene-precipitating solvent for reintroduction into the subsurface formation via the horizontal injection well.

269. The system of any one of claims 238 to 268, wherein the in situ bitumen recovery facility comprises a vaporization unit configured to vaporize the asphaltene-precipitating solvent at surface prior to supplying to the horizontal injection well for introduction as a vapor phase.

270. The system of any one of claims 238 to 269, wherein the thermal treatment facility is configured such that the deasphalted bitumen is maintained in liquid phase during the thermal treatment to cause a transfer of hydrogen from the heavy fraction to the light fraction directly in the liquid phase.

271. The system of any one of claims 238 to 270, wherein the thermal treatment vessel has a single product outlet for withdrawing the partially upgraded bitumen product from the thermal treatment vessel as a single stream.

272. The system of claim 271, wherein the thermal treatment facility further comprises a gas separator configured to receive the single stream of partially upgraded bitumen Date Recue/Date Received 2021-04-23 product and remove at least a portion of a gas phase from the partially upgraded bitumen product.

273. The system of any one of claims 238 to 272, wherein the thermal treatment facility comprises no external hydrogen addition unit.

274. The system of any one of claims 238 to 272, wherein the thermal treatment facility comprises an external hydrogen addition unit configured to add an external source of hydrogen to the deasphalted bitumen.

275. The system of any one of claims 238 to 272, wherein the thermal treatment facility comprises an external hydrogen addition unit configured to add a hydrogen transfer agent to the deasphalted bitumen.

276. The system of any one of claims 238 to 275, further comprising a dilution unit configured to receive the partially upgraded bitumen product from the thermal treatment facility and to dilute the partially upgraded bitumen product with a diluent to obtain a diluted bitumen product.

277. The system of any one of claims 238 to 276, further comprising a heat recovery unit configured to recover heat from the thermal treatment facility and to reuse at least a portion of the recovered heat in the in situ bitumen recovery facility.

278. The system of claim 277, wherein the heat is recovered from the partially upgraded bitumen product.

279. The system of claim 277 or 278, wherein the heat is at least partly reused for pre-heating a process stream of the in situ bitumen recovery facility prior to a unit operation.

280. The system of any one of claims 238 to 279, wherein the deasphalted bitumen has a variable composition over time.

281. The system of claim 280, wherein the deasphalted bitumen has a higher asphaltene content during an earlier stage of operating the in situ bitumen recovery facility, and a lower asphaltene content during a later stage of operating the in situ bitumen recovery facility.
Date Recue/Date Received 2021-04-23

282. The system of claim 281, wherein the earlier stage comprises a startup stage, and the later stage comprises a normal operation stage of the in situ bitumen recovery facility.

283. The system of any one of claims 280 to 282, further comprising a control system configured to control the in situ bitumen recovery facility or the thermal treatment or a combination thereof, based on the variable composition of the deasphalted bitumen.

284. The system of claim 283, wherein the control system is configured to control operation of the thermal treatment facility at lower severity conditions when the deasphalted bitumen has a higher asphaltene content, and at higher severity conditions when the deasphalted bitumen has a lower asphaltene content.

285. The system of claim 283, wherein the control system is configured to continuously control the thermal treatment facility based on the variable composition of the deasphalted bitumen.

286. The system of claim 283, wherein the control system is configured to intermittently control the thermal treatment facility based on the variable composition of the deasphalted bitumen.
Date Recue/Date Received 2021-04-23