CN113337266B - Fracturing fluid system for enhancing pressure bearing capacity of proppant and application method thereof - Google Patents

Abstract

The invention discloses a fracturing fluid system for enhancing the pressure bearing capacity of proppant, which comprises fracturing fluid and modified proppant; p-chlorophenyl acrylate, N-phenylacrylamide, acryloyl imidazole, N,N-methylenebisacrylamide, divinylbenzene, 1,3-bis(1-methylvinyl)benzene, azo One or at least two of diisobutyronitrile, benzoyl peroxide, dicumyl peroxide, and di-tert-butyl peroxide compound. Modified proppants are used modifiers for γ-(methacryloyloxy)propyltrimethoxysilane, vinyltrimethoxysilane, vinyl-tris(2-methoxyethoxy)silane One of a kind. The fracturing fluid reinforcing component of the present invention will spontaneously adsorb and spread on the surface of the modified proppant to form a tough coating layer, which can increase the lipophilic performance of the proppant and enhance the oil and gas conductivity. Increase oil and gas production.

Description

Fracturing fluid system for enhancing proppant pressure bearing capacity and using method thereof

technical field

The invention relates to the technical field of oil and gas exploitation, in particular to a fracturing fluid for enhancing the pressure-bearing capacity of a fracturing proppant and a use method thereof.

Background technique

Hydraulic fracturing technology, as the main measure for oil and gas well stimulation and water well injection, has been widely used in the development of low-permeability/ultra-low-permeability oil and gas fields, and is one of the most important measures to increase and stabilize production in oil and gas fields. The process of hydraulic fracturing is to pump high-viscosity pre-fluid into the target reservoir, and form extended fractures in the formation with a high pressure exceeding the fracture pressure of the formation; then inject sand-carrying fluid mixed with proppant into the formed fractures, so that The proppant is spread in the fracture; finally, the sand-carrying fluid is broken and viscous-reduced into a low-viscosity fluid, which flows to the wellbore and returns to the surface. Through this technology, a high-conductivity flow channel formed by proppant supporting the fracture wall is left in the formation, so as to facilitate the flow of oil and gas from the far-well formation to the bottom of the well.

After the hydraulic fracturing construction is completed, the conductivity of artificial fractures is an important parameter to evaluate the success of the construction, which is mainly affected by the proppant laying efficiency and proppant supporting capacity. Among them, the laying efficiency is controlled by the construction process, while the pressure bearing capacity is determined by the material itself. With the development of oil and gas resources to deeper formations, the requirements for proppant are also increased, and higher requirements are put forward for the performance of proppant, especially the compressive strength. Compared with quartz sand proppant, which is cheaper and has a wide range of sources, in order to meet the requirements of improving the compressive capacity, film-coated proppant or ceramsite proppant has to be used. Both of the latter two proppants are expensive due to the complicated preparation process. Much higher than that of quartz sand proppant. In addition, conventional ceramsite proppants usually have a high density, which has the problem of poor portability; if the density is reduced, the price of ceramsite proppants will be further greatly increased.

Therefore, in the context of the current large-scale promotion of hydraulic fracturing technology, a technology that can simultaneously meet the requirements of strong pressure bearing capacity, low price, and simple operation will provide a great boost to the development of my country's oil and gas energy.

Contents of the invention

The object of the present invention is to provide a fracturing fluid system capable of enhancing the pressure bearing capacity of the proppant and a method for using the fracturing fluid system in view of the above-mentioned defects existing in the existing proppant for fracturing.

The fracturing fluid system for enhancing the pressure bearing capacity of proppant provided by the invention includes fracturing fluid and modified proppant.

The fracturing fluid includes a base fluid and a reinforcing component, and the reinforcing component is phenyl methacrylate, p-chlorophenyl methacrylate, N-phenylacrylamide, acryloyl imidazole, N,N-methylenebis Acrylamide, divinylbenzene, 1,3-di(1-methylvinyl)benzene, azobisisobutyronitrile, benzoyl peroxide, dicumyl peroxide, di-tert-butyl peroxide A combination of one or at least two.

The base fluid of the fracturing fluid contains conventional components, and the conventional components are selected from guar gum, hydroxypropyl guar gum, hydroxyethyl cellulose, anionic polyacrylamide, polyvinyl alcohol, polyethylene glycol, glutaraldehyde, Dodecyldimethylbenzylammonium chloride, tetramethylammonium chloride, potassium chloride, ammonium chloride, sodium dodecylsulfonate, sodium dodecylbenzenesulfonate, alpha-olefinsulfonic acid One or more complexes of sodium, cocamidosulfobetaine, lauramidopropyl betaine, and lauryl glucoside.

In the fracturing fluid, the reinforcing component and the base fluid are used in a weight ratio of 0.1-10 parts: 90-99.9 parts; a preferred ratio is 1:99. The parts by weight of the reinforcement component and the base fluid add up to 100 parts.

The modified proppant is a conventional proppant that has been surface-modified by a modifier. The conventional proppant can be desert sand and conventional quartz sand with poor pressure bearing capacity, or coated sand, ceramsite and steel slag with strong pressure bearing capacity. The modifier is γ-(methacryloyloxy)propyltrimethoxysilane, vinyltrimethoxysilane, vinyl-tris(2-methoxyethoxy)silane, vinyltriethoxy One or more complexes of base silanes.

The modified proppant is made by the following method: adding the conventional proppant into the ethanol solution containing the modifier, stirring evenly, standing still, after the surface of the conventional proppant is fully wetted, filtering and drying to obtain the modified proppant Proppant.

The above-mentioned method of using the fracturing fluid system for enhancing the pressure bearing capacity of the proppant, the steps are as follows:

(1) Prepare the base liquid and the reinforcement component separately on the ground;

(2) Mix the prepared base fluid, reinforcing component and modified proppant, and stir evenly at a high speed to form a sand-carrying fluid;

(3) The sand-carrying liquid is transported into the artificial fractures by hydraulic fracturing vehicles;

(4) After adding sand, shut down and stabilize for 20-120 minutes;

(5) Open the wellhead and discharge the fracturing fluid.

Under formation conditions, the reinforcing components in the fracturing fluid can be combined with the modified proppant to enhance the pressure bearing capacity of the original proppant through covalent or non-covalent bonds. The reinforcing component will spontaneously adsorb and spread on the surface of the modified proppant, and as the temperature rises, a tough coating layer will be formed on the surface of the proppant. The coating layer can increase the contact area between the proppants and prevent the proppants from breaking under formation closure pressure. At the same time, the coating layer can increase the lipophilic performance of the proppant and enhance the oil and gas conductivity.

The fracturing fluid of the present invention has both the transmission power of ordinary fracturing fluid and the energy efficiency of carrying proppant. At the same time, the fracturing fluid can enhance the pressure bearing capacity of proppant and improve the pressure bearing capacity of proppant whose fracture rate cannot meet the construction requirements. ability, so that it can support artificial fractures, maintain high-permeability diversion channels, and improve the production efficiency of oil and gas fields.

Compared with the prior art, the benefits of the present invention are:

(1) The fracturing fluid of the present invention can enhance the pressure-bearing capacity of the fracturing proppant and increase the application range of the existing cheap proppant products.

(2) The pressure-bearing capacity of the enhanced fracturing proppant of the present invention can reach or even exceed the pressure-bearing capacity of the corresponding film-coated proppant, but the proppant of the present invention does not require a film-coating process, which saves the corresponding cost of the film-coated proppant .

(3) The enhanced fracturing proppant of the present invention can effectively enhance the interaction between different proppant particles, prevent fracturing fluid flowback and sand production during production, and reduce the risk of pipelines being worn by proppant.

(4) The construction process of the fracturing fluid for enhancing proppant pressure bearing capacity of the present invention is simple to prepare, does not need to add additional equipment, and will not increase construction costs.

(5) The reinforcing component of the present invention will spontaneously adsorb and spread on the surface of the modified proppant to form a tough film layer, which can increase the lipophilic performance of the proppant and enhance the oil and gas flow capacity, Increase oil and gas production and increase economic benefits.

Other advantages, objectives and features of the present invention will partly be embodied through the following descriptions, and partly will be understood by those skilled in the art through the study and practice of the present invention.

Description of drawings

Fig. 1 is a working principle diagram of the fracturing fluid system for enhancing proppant pressure bearing capacity of the present invention.

Detailed ways

The preferred embodiments of the present invention will be described below in conjunction with the accompanying drawings. It should be understood that the preferred embodiments described here are only used to illustrate and explain the present invention, and are not intended to limit the present invention.

The working principle of the fracturing fluid system for enhancing proppant pressure bearing capacity of the present invention is shown in FIG. 1 . The first stage (surface and wellbore): first put the base fluid of the fracturing fluid, the reinforcing component and the modified proppant into the same container, stir at high speed to disperse evenly, and obtain the sand-carrying fluid, and then use the fracturing pump truck to transport the sand-carrying fluid Pumped into the ground, at this stage the reinforcing components are evenly dispersed in the system in the form of small droplets. In the second stage (in the fracture), as the sand-carrying fluid enters the fractures at all levels of the formation, the modified proppant gradually settles and piles up due to the influence of gravity, and there are a large number of gaps between the particles, which can be filled with reinforcing components. In the third stage (well shut-in), with the end of the fracturing operation, the well is blocked for a period of time. At this time, the enhanced components are adsorbed and spread on the surface of the modified proppant, and as the temperature rises, through covalent bonds or non-covalent Valence bonds form a layer of film on the surface of the proppant to enhance the compressive capacity of the proppant.

Example 1

A preparation method of surface modified quartz sand, comprising the following steps:

(1) Weigh 2 parts of γ-(methacryloyloxy)propyltrimethoxysilane, 1 part of vinyltrimethoxysilane and 300 parts of ethanol, add them into the container, stir and mix evenly to obtain the mixed solution A, Store at 5-25°C until use.

(2) Weigh 100 parts of dry 20/40 mesh conventional quartz sand and 20 parts of mixed solution A, add them to the container, stir evenly, and let stand for 5 minutes until the mixed solution A fully wets the surface of the quartz sand to obtain the mixture B .

(3) The mixture B was transferred to an oven at 90°C and dried for 60 minutes to obtain a surface-modified quartz sand proppant.

Example 2

A preparation method of surface modified desert sand, comprising the following steps:

(1) Weigh 2 parts of γ-(methacryloyloxy)propyltrimethoxysilane, 1 part of vinyl-tris(2-methoxyethoxy)silane and 300 parts of ethanol, and add them to the container, Stir and mix evenly to obtain the mixed liquid A, which is stored at 5-25°C until use.

(2) Weigh 100 parts of dry 40/70 mesh conventional desert sand and 20 parts of mixed solution A, add them into the container, stir evenly, and let stand for 5 minutes until the mixed solution A fully wets the surface of the quartz sand to obtain the mixture B .

(3) The mixture B was transferred to an oven at 80°C and dried for 90 minutes to obtain a surface-modified desert sand proppant.

Example 3

A preparation method of surface modified ceramsite, comprising the following steps:

(1) Weigh 2 parts of γ-(methacryloyloxy)propyltrimethoxysilane, 1 part of vinyltriethoxysilane and 300 parts of ethanol, add them into the container, stir and mix evenly to obtain the mixed solution A , Store at 5-25°C for later use.

(2) Weigh 150 parts of dry 40/70 mesh ceramsite and 20 parts of mixed solution A, add them into the container, stir evenly, and let stand for 5 minutes until the mixed solution A fully wets the surface of the quartz sand to obtain the mixture B.

(3) The mixture B was transferred to an oven at 100°C and dried for 30 minutes to obtain a surface-modified ceramsite proppant.

Example 4

An implementation effect of a fracturing fluid system that enhances proppant pressure bearing capacity, comprising the following steps:

(1) Weigh 100 parts of phenyl methacrylate, 20 parts of N-phenylacrylamide, 3 parts of N,N-methylenebisacrylamide, 1.5 parts of azobisisobutyronitrile, and 1.5 parts of benzyl peroxide Acyl in the container, stir and mix evenly to obtain the mixed solution A, which is the reinforcing component, and store it at 0-5°C until use.

(2) Take by weighing 1 part of guar gum, 0.5 part of polyvinyl alcohol, 0.5 part of dodecyldimethylbenzyl ammonium chloride, 1 part of tetramethylammonium chloride, 0.5 part of sodium dodecylsulfonate, Put 0.5 parts of cocoamidosulfobetaine in a container, add 100 parts of water, stir and mix evenly to obtain a mixed solution B, which is the base solution, and store it at 5-25°C until use.

(3) Weigh 0.5 parts of mixed solution A, 99.5 parts of mixed solution B and 30 parts of the modified quartz sand proppant prepared in Example 1 into a container, stir and mix evenly to obtain mixture C, which is the sand-carrying solution.

(4) The mixture C was transferred to an oven at 60°C, and after standing for 120 minutes, the solid particles were collected by filtration and washed with tap water.

(5) Dry the solid particles in an oven at 105° C. for 30 minutes to obtain quartz sand proppant D.

(6) Take the quartz sand proppant D and the initial unmodified 20/40 mesh quartz sand of Example 1, and measure the breakage rate at 35 MPa. The results are shown in Table 1.

Table 1. Fracture rate of 20/40 mesh quartz sand and quartz sand proppant D

Proppant 20/40 mesh quartz sand Quartz sand proppant D Broken rate 14.8% 5.2%

It can be seen from the data in Table 1 that the pressure bearing capacity of the quartz sand proppant D enhanced by the fracturing fluid of the present invention is significantly higher than that of ordinary quartz sand.

Example 5

An implementation effect of a fracturing fluid system for enhancing proppant pressure bearing capacity, comprising the following steps:

(1) Weigh 100 parts of phenyl methacrylate, 10 parts of chlorophenyl methacrylate, 5 parts of divinylbenzene, 1.5 parts of azobisisobutyronitrile, and 1.5 parts of dicumyl peroxide in a container, Stir and mix evenly to obtain the mixed solution A, which is the reinforcing component, and store it at 0-5°C until use.

(2) Weigh 1 part of hydroxypropyl guar gum, 0.5 part of polyethylene glycol, 0.5 part of dodecyldimethylbenzyl ammonium chloride, 1 part of potassium chloride, 0.5 part of dodecylbenzenesulfonic acid Sodium, 0.5 parts of lauryl amidopropyl betaine, add 100 parts of pure water into a container, stir and mix evenly to obtain mixed liquid B, which is the base liquid, and store at 5-25°C until use.

(3) Weigh 1 part of mixed solution A, 99 parts of mixed solution B and 30 parts of the modified desert sand proppant prepared in Example 2, put them in a container, stir and mix evenly, and obtain mixture C.

(4) The mixture C was transferred to an oven at 90°C, and after standing for 60 minutes, the solid particles were collected by filtration and washed with tap water.

(5) Dry the solid particles in an oven at 105° C. for 30 minutes to obtain desert sand proppant D.

(6) Take the unmodified 40/70 mesh desert sand described in Example 2 and the self-made desert sand proppant D, and measure the fracture rate at 35 MPa. The results are shown in Table 2.

Table 2. Breakage rate of 40/70 mesh desert sand and self-made desert sand proppant D

Proppant 20/40 mesh desert sand Desert sand proppant D Broken rate 28.4% 11.3%

It can be seen from the data in Table 2 that the pressure bearing capacity of the desert sand proppant D enhanced by the fracturing fluid of the present invention is significantly higher than that of ordinary desert sand.

Example 6

A fracturing fluid implementation effect for enhancing proppant pressure bearing capacity, comprising the following steps:

(1) Weigh 100 parts of phenyl methacrylate, 25 parts of acryloyl imidazole, 3 parts of 1,3-bis(1-methylvinyl)benzene, 1.5 parts of azobisisobutyronitrile, 1.5 parts of benzene peroxide Formyl, in a container, stir and mix evenly to obtain a mixture A, which is the reinforcing component, and store it at 0-5°C until use.

(2) Weigh 0.1 part of anionic polyacrylamide, 0.5 part of polyvinyl alcohol, 0.5 part of dodecyl dimethyl benzyl ammonium chloride, 1 part of ammonium chloride, 0.5 part of sodium α-olefin sulfonate (dodecyl sulfonate) carbon), 0.5 parts of dodecyl glucoside, in a container, add 100 parts of pure water, stir and mix evenly to obtain mixed solution B, which is the base solution, and store it at 5-25°C for later use.

(3) Weigh 0.5 parts of mixed solution A, 99.5 parts of mixed solution B and 30 parts of the modified ceramsite proppant prepared in Example 3, put them in a container, stir and mix evenly, and obtain mixture C.

(4) The mixture C was transferred to an oven at 120°C, and after standing for 30 minutes, the solid particles were collected by filtration and washed with tap water.

(5) Dry the solid particles in an oven at 105°C for 30 minutes to obtain ceramsite proppant D.

(6) Take the unmodified 40/70 mesh ceramsite and ceramsite proppant D described in Example 3, and measure the breakage rate at 70 MPa. The results are shown in Table 3.

Table 3. Breakage rate of 20/40 mesh ceramsite and self-made ceramsite proppant D

Proppant 20/40 mesh ceramsite Ceramsite proppant D Broken rate 3.2% 2.2%

It can be seen from the data in Table 3 that the pressure bearing capacity of the ceramsite proppant D enhanced by the fracturing fluid of the present invention is significantly higher than that of ordinary ceramsite.

The above description is only a preferred embodiment of the present invention, and does not limit the present invention in any form. Although the present invention has been disclosed as above with preferred embodiments, it is not intended to limit the present invention. Anyone familiar with this field Those skilled in the art, without departing from the scope of the technical solution of the present invention, can use the technical content disclosed above to make some changes or modify equivalent embodiments with equivalent changes, but all the content that does not depart from the technical solution of the present invention, according to the present invention Any simple modifications, equivalent changes and modifications made to the above embodiments by the technical essence still belong to the scope of the technical solutions of the present invention.

Claims (7)

1. A fracturing fluid system for enhancing the bearing capacity of a propping agent is characterized by comprising a fracturing fluid and a modified propping agent;

the fracturing fluid comprises base fluid and a reinforcing component, wherein the reinforcing component is formed by combining three types of raw materials and comprises a polymerizable monomer, a cross-linking agent and an initiator; the polymerizable monomer is one or the composition of at least two of phenyl methacrylate, p-chlorophenyl methacrylate, N-phenyl acrylamide and acryloyl imidazole; the cross-linking agent is one or the composition of at least two of N, N-methylene bisacrylamide, divinylbenzene and 1, 3-di (1-methylvinyl) benzene; the initiator is one or the composition of at least two of azodiisobutyronitrile, benzoyl peroxide, dicumyl peroxide and ditert-butyl peroxide;

the modified proppant is a conventional proppant subjected to surface modification by a modifier, and the modifier is one or a plurality of compounds of gamma- (methacryloyloxy) propyl trimethoxy silane, vinyl-tri (2-methoxyethoxy) silane and vinyl triethoxy silane.

2. The fracturing fluid system for enhancing the bearing capacity of the proppant as set forth in claim 1, wherein the conventional proppant is one of desert sand, quartz sand, precoated sand, ceramsite and steel slag.

3. The fracturing fluid system of claim 2, wherein the modified proppant is made by a method comprising: adding the conventional proppant into an ethanol solution containing the modifier, uniformly stirring, standing, fully wetting the surface of the conventional proppant, filtering, and drying to obtain the modified proppant.

4. A fracturing fluid system for enhancing the pressure bearing capacity of a proppant as set forth in claim 1, wherein said base fluid comprises conventional components selected from one or more of guar, hydroxypropyl guar, hydroxyethyl cellulose, anionic polyacrylamide, polyvinyl alcohol, polyethylene glycol, glutaraldehyde, dodecyl dimethyl benzyl ammonium chloride, tetramethyl ammonium chloride, potassium chloride, ammonium chloride, sodium dodecyl sulfate, sodium dodecyl benzene sulfonate, sodium alpha olefin sulfonate, cocamido hydroxysulfobetaine, lauramidopropyl betaine, dodecyl glycoside.

5. The fracturing fluid system for enhancing the bearing capacity of the proppant as set forth in claim 4, wherein the amount of the reinforcing component and the base fluid in the fracturing fluid is 0.1-10 parts by weight: 90-99.9 parts; the weight parts of the reinforcing component and the base fluid are 100 parts in total.

6. The use method of the fracturing fluid system for enhancing the bearing capacity of the propping agent as recited in any of claims 1 to 5, characterized in that a base fluid and a reinforcing component are respectively prepared on the ground, and the base fluid, the reinforcing component and the modified propping agent are uniformly mixed to form a sand-carrying fluid; then conveying the sand-carrying liquid into the artificial cracks, and closing the well for stabilizing for 20-120 minutes after the sand is added; and finally opening the well mouth and discharging the fracturing fluid back.

7. The method of using a fracturing fluid system with enhanced proppant containment capability of claim 6, comprising the steps of:

(1) Respectively preparing base liquid and reinforcing components on the ground;

(2) Mixing the prepared base fluid, the reinforcing component and the modified propping agent, and uniformly stirring at a high speed to form a sand-carrying fluid;

(3) Conveying the sand-carrying liquid into artificial cracks through a hydraulic fracturing truck;

(4) Closing the well and stabilizing for 20-120 minutes after the sand is added;

(5) And opening the well mouth and discharging the fracturing fluid back.

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