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GB2131471A - Adsorption reducing composition - Google Patents

Adsorption reducing composition Download PDF

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Publication number
GB2131471A
GB2131471A GB08331490A GB8331490A GB2131471A GB 2131471 A GB2131471 A GB 2131471A GB 08331490 A GB08331490 A GB 08331490A GB 8331490 A GB8331490 A GB 8331490A GB 2131471 A GB2131471 A GB 2131471A
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GB
United Kingdom
Prior art keywords
oil
cellulose ether
composition according
reservoir
composition
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
GB08331490A
Other versions
GB8331490D0 (en
GB2131471B (en
Inventor
Ian Charles Callaghan
John Howard Clint
Philip Kenneth Gordon Hodgson
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BP PLC
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BP PLC
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Publication date
Application filed by BP PLC filed Critical BP PLC
Priority to GB08331490A priority Critical patent/GB2131471B/en
Publication of GB8331490D0 publication Critical patent/GB8331490D0/en
Publication of GB2131471A publication Critical patent/GB2131471A/en
Application granted granted Critical
Publication of GB2131471B publication Critical patent/GB2131471B/en
Expired legal-status Critical Current

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    • CCHEMISTRY; METALLURGY
    • C09DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09KMATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K8/00Compositions for drilling of boreholes or wells; Compositions for treating boreholes or wells, e.g. for completion or for remedial operations
    • C09K8/60Compositions for stimulating production by acting on the underground formation
    • C09K8/84Compositions based on water or polar solvents
    • C09K8/86Compositions based on water or polar solvents containing organic compounds
    • C09K8/88Compositions based on water or polar solvents containing organic compounds macromolecular compounds
    • C09K8/90Compositions based on water or polar solvents containing organic compounds macromolecular compounds of natural origin, e.g. polysaccharides, cellulose

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  • Chemical & Material Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Organic Chemistry (AREA)
  • Water Treatment By Sorption (AREA)

Abstract

A composition, suitable for use in reducing the adsorption of a surfactant onto the structure of a crude oil reservoir in the course of enhanced oil recovery, comprises an aqueous saline solution or dispersion of a cellulose ether. The ether is preferably sulphonated hydroxyethyl cellulose.

Description

SPECIFICATION Adsorption reducing composition This invention relates to a composition suitable for use in reducing the adsorption of a surfactant onto the structure of a crude oil reservoir in the course of enhanced oil recovery.
A petroleum reservoir is formed by a suitably shaped porous stratum of rock sealed with an impervious rock. The nature of the reservoir rock is extremely important as the oil is present in the small spaces or pores which separate the individual rock grains.
Crude oil is generally found in a reservoir in association with water, which is often saline, and gas. Dependent upon the characteristics of the crude, the temperature and the pressure, the gas may exist in solution in the oil or as a separate phase in the form of a gas cap. The oil and gas occupy the upper part of the reservoir and below there may be a considerable volume of water, known as the aquifer, which extends throughout the lower levels of the rock.
For oil to move through the pores of the reservoir rock and into a well, the pressure under which the oil exists in the reservoir must be greater than the pressure at the well.
The water contained in the aquifer is under pressure and is one source of drive. The dissolved gas associated with the oil is another and so is the free gas in the gas cap when this is present.
A time may come in the life of an oilfield when the natural pressure of the reservoir declines to such an extent that it is no longer sufficiently large to force the oil out of the pores of the rock into the well. This stage can be reached before the greater part of the oil is recovered from the reservoir.
Formerly it was the practice to rely on natural drive for as long as possible, only resorting to artificial production methods when the natural pressure dropped too low to sustain a reasonable flow. However, it has now been established that ,the eventual recovery of oil from a reservoir can be much greater if the pressure is not allowed to drop significantly in the early stages of production. Similarly, by utilising artificial means of maintaining pressure early in the life of a reservoir, production offlake rates may often be adjusted to economic advantage.
Thus in order to maintain pressure, or to accelerate the natural drive, or to initiate a drive where none occurs naturally, it is frequently necessary to employ the technique known as secondary recovery. The simplest method of forcing the oil out of the reservoir rock is by direct displacement with another fluid. When water is used, the secondary recovery process is called water flooding.
Water flooding is one of the most successful and extensively used secondary recovery methods. Water is injected under pressure into the reservoir rock via injection wells and drives the oil through the rock into nearby producing wells.
However, water does not displace crude oil with high efficiency because water and oil are immiscible, and also because the interfacial tension between water and oil is high. This weakness of water flooding has been recognised and many surfactants have been proposed for decreasing the interfacial tension between water and crude oil.
Other attempts to increase the recovery of crude oil from a reservoir by water flooding have suggested modifying the surface of the reservoir rock by treating it with a polymer or surfactant which is adsorbed by the surface and alters its wettability.
Unfortunately, several types of interactions which hinder oil recovery may occur between the recovery reagent(s) and the reservoir rock or brine. For example, reagent(s) may be adsorbed from the flood onto the reservoir rocks, depleting the flood of its active constituent(s). To counteract this it has been proposed that relatively inexpensive compounds, known as "sacrificial agents", should be added to the flood to satisfy some of the adsorption sites in the reservoir rock. Polyvalent cations (e.g. Ca++, Mg++) in the brine may decrease oil production by precipitating the polymer or surfactant from the flood or scale from sea water when this is used as the aqueous component of the flood. Other ions in the reservoir brine can also hinder the effectiveness of the polymer or surfactant flood.A low salt-containing, aqueous preflush may be injected ahead of the flood to provide a favourable environment for the flood.
We have now discovered a composition which reduces the adsorption of a surfactant onto the formation rock of a crude oil reservoir.
Thus, according to the present invention there is provided a composition suitable for reducing the adsorptivity of an undergound porous rock formation, which composition comprises an aqueous saline solution or dispersion of a cellulose ether.
The preferred ether is hydroxyethyl cellulose.
Optionally, at least 10% of the reactive sites in the original ether are substituted by sulphonate groups.
The composition may also contain an ionic or non-ionic surfactant of the type used in enhanced oil recovery. Alternatively, the latter may be utilised subsequently.
The pH of the dispersion is preferably less than 7.
The aqueous saline component of the dispersion is suitably sea water, where this is readily available. Since sea water is usually slightly alkaline it should be acidified before use.
The concentration of the cellulose ether in the dispersion is preferably in the range 0.005 to 0.5% by weight.
The ratio of the concentration of the cellulose ether to the anionic and/or non-ionic surfactant is suitably in the range 1:25 to 1:2.
Conveniently the sulphonated compound may be prepared by reacting the cellulose ether with a sulphonating agent, e.g., 1,3-propanesultone.
According to another aspect of the present invention, there is provided a method for treating an oil-bearing formation to reduce the tendency of surfactants to adsorb thereon in the presence of crude oil which method comprises contacting the formation with a composition as hereinbefore described.
The invention is illustrated by the folowing Examples.
Example 1 is provided for comparative purposes only and in itself does not illustrate an embodiment of the invention.
Example 1 Dinonylphenoxy-(CH2CH2O)7(CH2)3SO3Na was dissolved in filtered sea water to give a solution containing 2,000 ppm surfactant. The pH of the sea water had previously been adjusted to 6.5.
This solution was pumped through a stainless steel column packed with unconsolidated core material from the Forties crude oil reservoir maintained at 960C. The concentration of surfactant in the effluent solution was monitored continuously using an inline UV detector.
Monitoring continued until the detector indicated that the concentrate of the surfactant in the effluent equalled the concentration in the feed. At this point adsorption was deemed to be complete.
From calibration graphs of detector responses against concentration and a knowledge of the dead volume of the system the adsorption of the surfactant expressed in mg of surfactant per gram of substrate was calculated. This was found to be 1.09 mg/g.
Example 2 Example 1 was repeated with the difference that the saline solution additionally contained 500 ppm sulphonated hydroxyethyl cellulose (degree of sulphonation 0.5). This polymer does not give a UV signal and therefore adsorption figures relate only to the surfactant. The adsorption of the latter was calculated to be 0.75 mg/g.
Thus the presence of the polymer results in a significant reduction in the adsorption of the surfactant.

Claims (7)

Claims
1. A composition suitable for reducing the adorptivity of an underground porous rock formation, which composition comprises an aqueous saline solution or dispersion of a cellulose ether.
2. A composition according to claim 1 wherein the cellulose ether is hydroxyethyl cellulose.
3. A composition according to either of the preceding claims wherein at least 10% of the reactive sites origionally present in the cellulose ether are substituted by sulphonate groups.
4. A composition according to any of the preceding claims wherein the concentration of the cellulose ether in the dispersion is in the range 0.005 to 0.5% by weight.
5. A composition according to any of the preceding claims also comprising an anionic and/or non-ionic surfactant of the type used in enhanced oil recovery.
6. A compositoin according to claim 5 wherein the ratio of the concentration of the cellulose ether to the anionic and/or non-ionic surfactant is in the range 1:25 to 1:2.
7. A method for treating an oil-bearing formation to reduce the tendency of surfactants to absorb thereon in the presence of crude oil which method comprises contacting the formation with a composition according to any of the preceding claims.
GB08331490A 1982-12-09 1983-11-25 Adsorption reducing composition Expired GB2131471B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB08331490A GB2131471B (en) 1982-12-09 1983-11-25 Adsorption reducing composition

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB8235142 1982-12-09
GB08331490A GB2131471B (en) 1982-12-09 1983-11-25 Adsorption reducing composition

Publications (3)

Publication Number Publication Date
GB8331490D0 GB8331490D0 (en) 1984-01-04
GB2131471A true GB2131471A (en) 1984-06-20
GB2131471B GB2131471B (en) 1986-10-22

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Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN107709510A (en) 2015-06-10 2018-02-16 罗地亚经营管理公司 Phosphonated polysaccharides and gels and methods for their preparation

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1541759A (en) * 1976-09-20 1979-03-07 Halliburton Co Fluids for use in oil wells
GB1549734A (en) * 1977-06-02 1979-08-08 Int Drilling Fluids Ltd Preparation of slurries
GB2055106A (en) * 1979-06-29 1981-02-25 Union Carbide Corp Aqueous solutions containing crosslinked hydroxyethyl carboxyethyl cellulose and their use
GB2075041A (en) * 1980-05-05 1981-11-11 Nl Industries Inc Compositions and method for thickening aqueous brines
EP0046671A2 (en) * 1980-08-25 1982-03-03 Hercules Incorporated Method of thickening heavy brine solutions
EP0049191A1 (en) * 1980-09-26 1982-04-07 Elf Atochem S.A. Process for preparing completion fluids, and pastes used in carrying out the process
GB2090308A (en) * 1980-12-29 1982-07-07 Mobil Oil Corp Stabilized solutions of modified cellulose in brine and their use as completion and workover fluids
EP0061685A2 (en) * 1981-03-31 1982-10-06 Hoechst Aktiengesellschaft Gel-forming composition based on a cellulose ether, process for preparing a gel, process for the reversible destruction of this gel and its use in secondary oil recuperation

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1541759A (en) * 1976-09-20 1979-03-07 Halliburton Co Fluids for use in oil wells
GB1549734A (en) * 1977-06-02 1979-08-08 Int Drilling Fluids Ltd Preparation of slurries
GB2055106A (en) * 1979-06-29 1981-02-25 Union Carbide Corp Aqueous solutions containing crosslinked hydroxyethyl carboxyethyl cellulose and their use
GB2075041A (en) * 1980-05-05 1981-11-11 Nl Industries Inc Compositions and method for thickening aqueous brines
EP0046671A2 (en) * 1980-08-25 1982-03-03 Hercules Incorporated Method of thickening heavy brine solutions
EP0049191A1 (en) * 1980-09-26 1982-04-07 Elf Atochem S.A. Process for preparing completion fluids, and pastes used in carrying out the process
GB2090308A (en) * 1980-12-29 1982-07-07 Mobil Oil Corp Stabilized solutions of modified cellulose in brine and their use as completion and workover fluids
EP0061685A2 (en) * 1981-03-31 1982-10-06 Hoechst Aktiengesellschaft Gel-forming composition based on a cellulose ether, process for preparing a gel, process for the reversible destruction of this gel and its use in secondary oil recuperation

Also Published As

Publication number Publication date
GB8331490D0 (en) 1984-01-04
GB2131471B (en) 1986-10-22

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