CA1066041A - Flooding with micellar systems to solubilize equal volumes of hydrocarbon and water - Google Patents
Flooding with micellar systems to solubilize equal volumes of hydrocarbon and waterInfo
- Publication number
- CA1066041A CA1066041A CA255,604A CA255604A CA1066041A CA 1066041 A CA1066041 A CA 1066041A CA 255604 A CA255604 A CA 255604A CA 1066041 A CA1066041 A CA 1066041A
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- Canada
- Prior art keywords
- water
- crude oil
- micellar dispersion
- micellar
- cosurfactant
- Prior art date
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-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
- C09K8/00—Compositions for drilling of boreholes or wells; Compositions for treating boreholes or wells, e.g. for completion or for remedial operations
- C09K8/58—Compositions for enhanced recovery methods for obtaining hydrocarbons, i.e. for improving the mobility of the oil, e.g. displacing fluids
- C09K8/584—Compositions for enhanced recovery methods for obtaining hydrocarbons, i.e. for improving the mobility of the oil, e.g. displacing fluids characterised by the use of specific surfactants
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- Chemical & Material Sciences (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Life Sciences & Earth Sciences (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Organic Chemistry (AREA)
- Colloid Chemistry (AREA)
- Emulsifying, Dispersing, Foam-Producing Or Wetting Agents (AREA)
- Production Of Liquid Hydrocarbon Mixture For Refining Petroleum (AREA)
- Liquid Carbonaceous Fuels (AREA)
- Extraction Or Liquid Replacement (AREA)
Abstract
FLOODING WITH MICELLAR SYSTEM TO SOLUBILIZE
EQUAL VOLUMES OF HYDROCARBON AND WATER
ABSTRACT OF THE DISCLOSURE
Improved oil recovery by flooding subterranean for-mations with micellar dispersions comprised of hydrocarbon, water, cosurfactant, surfactant, and optionally electrolyte is obtained by designiny the micellar dispersion to solu-bilize about equal volumes of connate water and crude oil within the subterranean formation. Such is accomplished by selecting a particular cosurfactant and adjusting the concentration of the cosurfactant to obtain the desired solubilization characteristics.
EQUAL VOLUMES OF HYDROCARBON AND WATER
ABSTRACT OF THE DISCLOSURE
Improved oil recovery by flooding subterranean for-mations with micellar dispersions comprised of hydrocarbon, water, cosurfactant, surfactant, and optionally electrolyte is obtained by designiny the micellar dispersion to solu-bilize about equal volumes of connate water and crude oil within the subterranean formation. Such is accomplished by selecting a particular cosurfactant and adjusting the concentration of the cosurfactant to obtain the desired solubilization characteristics.
Description
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. .
BACKGROUND OF THE INVENTION
16 Field of the Invention 17 This invention relates to injecting a micellar dis-18 persion into a subterranean formation and displacing it 19 toward a production means in fluid communication with the formation to recover crude oil therethrough.
21 Description of the Prior Art 22 Micellar dispersions are useful for recovering crude 23 oil from subterranean reservoirs, see for example U.S.
24 Patent Nos. 3,254,714; 3,275,075; 3,506,070; 3,497,006;
3,613,786; 3,734,185; 3,740,343; 3,827,A96; and other 26 patents defining surfactant systems and assigned to Marathon 27 Oil Company, Esso Production Research Company; Shell Oil 28 Company; Union Oil Company, Mobil Oil Company, Texaco Oil 29 Company, etc. The micellar dispersion is injected into the formation followed by a mobility buffer and then a water 31 drive to displace crude oil from the formation.
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1 Patents representative of the prior art include:
. .
BACKGROUND OF THE INVENTION
16 Field of the Invention 17 This invention relates to injecting a micellar dis-18 persion into a subterranean formation and displacing it 19 toward a production means in fluid communication with the formation to recover crude oil therethrough.
21 Description of the Prior Art 22 Micellar dispersions are useful for recovering crude 23 oil from subterranean reservoirs, see for example U.S.
24 Patent Nos. 3,254,714; 3,275,075; 3,506,070; 3,497,006;
3,613,786; 3,734,185; 3,740,343; 3,827,A96; and other 26 patents defining surfactant systems and assigned to Marathon 27 Oil Company, Esso Production Research Company; Shell Oil 28 Company; Union Oil Company, Mobil Oil Company, Texaco Oil 29 Company, etc. The micellar dispersion is injected into the formation followed by a mobility buffer and then a water 31 drive to displace crude oil from the formation.
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1 Patents representative of the prior art include:
2 Gogarty et al in U.S. 3,443,635 teach that the hydro-
3 carbon and water can be simultaneously displaced from the
4 formation by determining the relative permeabilities of the water and the oil in the reservoir, then calculating the 6 desired mobility of the displacing fluid.
7 Gogarty teaches in U.S, 3,493,051 improved flooding by 8 incorporating alkali metal hydroxide into the micellar 9 dispersion to make the dispersion more hydrophilic.
U.S. 3,507,331 and 3,520,365 to Jones define an im-11 proved method of designing the flooding system to impart 12 stability to the micellar dispersion.
13 Healy et al in "Physical Chemical Aspects of Micro-14 emulsion Flooding", Society of Petroleum Engineers ~ournal, 14 (5), Page 491, October, 1974, teaches optimization of a 16 microemulsion for oil recovery is obtained by adjusting the 17 electrolyte concentration to "optimal salinity".
18 Design of micellar systems for improved oil recovery is 19 usually effected with petroleum sulfonates, hydrocarbon, water, electrolyte, and one or more alcohols as the co-21 surfactants. Often, the choice of petroleum sulfonate, 22 is limited and may not be the optimum one for the connate 23 water and/or crude oil within the reservoir. As a result, 24 oil recoveries are generally lower than that desired if a more desirable surfactant could be used.
26 If the micellar dispersion is improperly constituted 27 such that it solubilizes a considerably larger volume of 28 connate water than it solubilizes crude oil, the high amount 29 of water take-up dilutes the surfactant concentration and reduces the micellar dispersion's ability to solubilize crude 31 oil--in some cases to zero. In such cases, the micellar dis-,, ;, .
. ~, ~ , . . . . : .
. , ~ .
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iOIl lo~e. Lts al)iliLy to disl)lncc cru(le oil at residual oil saturation and the oil recovery eff:icicncy is reduced.
On the otller hand, a micellar dispersion can be improperly designe~ to solubllize large amounts of crude oil, but little or no water. Again, oil recovery efficiency suffers because, although the micellar dispersion can readily displace crude oil from a reservoir rock, the aqueous mobility buffer and drive fluids are incapable of "miscibly" displacing the micellar dispersion; the latter can be left in the rock since its mobility 10 is reduced.
SUMMARY OF THE IN~E~TION
-Applicant has discovered that optimum oil recovery is obtained by designing the micellar dispersion to solubilize about equal volumes of connate water and the crude oil ~hydrocarbon) within the reservoir. This solubility characteristic is controlled, to a large degree, by selection of the proper type and concentration of cosurfactant used to prepare the micellar dispersion. Such a j selection is obtained from data resulting from solubilizing different amounts of connate water and crude oil at different 20 cosurfactant concentrations. The cosurfactant concentration at < which the solubilization or uptake of the hydrocarbon and connate . water is about equal, is the preferred design of the micellar dispersion to obtain maximum oil recovery.
In one particular aspect the present invention ~, provides in a process for recovering crude oil from a subterranean formation wherein a micellar dispersion comprised of water, hydro-carbon, surfactant, cosurfactant, and inorganic electrolyte is ~r, injected into the formation to displace crude oil therefrom, the improvement comprising injecting into the formation a micellar 30 dispersion which solubilizes substantially equal volumes of crude eon~e ' ~ oil and~water.
In another particular aspect the present inventlon jl/ ~- ~ -3-., ~ .
.
106t~041 ~ovi(l~ s l-ro(~ ; For ro(~ovorin~ crll(le oi1 From a .~uhterranean forma~iol1 w~rcin ~1 n~ ellar dispersiol1 con~pris:ing water, hydrocarbvn surfactant, cosurf~ctant, and inorgan:l.c ~l.ectrolyte is i.njected into the ~or~ation to displace crude oil Lherefrom, the .improvement comprlslng designing the miccl.lar dispers:ior1 to soluh.l.lize ~ ~ 0,7~l f ~
substant:i.al.1.y equal volumes o~ crude oil and ~ water and thereafter injecting the micellar dispers.ion into the formation and displacing it therethrough to recover crude oil.
In yet a Eurther particular aspect the present l0 invention provides in a process for recovering crude oil from a subterranean formation wherein a micellar dispersion comp~ising water, hydrocarbon, surfactant, inorganic electrolyte, and co-surfactant is injected into the formation followed by an aqueous mobility buffer to displace crude oil therefrom, the improvement comprising formulating the micellar dispersion to solubilize substantially equal volumes of the crude oil within the subterranean Ca~af e formation and thc water within the aqueous mobility buffer and , thereafter injecting the micellar dispersion and the aqueous mobility buffer into the subterranean formation to displace crude oil 20 therefrom.
BRIEF DESCRIPTION OF THE DRAWINGS
O Figure l represents the amount of connate water and crude oil that is solubilized by a micellar dispersion at different :
cosurfactant concentrations. The micellar dispersion composition ~ -is defined in E~ample I. At the junc-.
-.. .
jl/ .......................... -3a-~ .
,, 10~0~
7 ture of the connate water and crud~ oil uptake is the optimum 2 concentration of the cosurfactant for this particular system.
3 Figure 2 represents the percent oil recovery of a 4 micellar dispersion composition defined in Example II. The curves illustrate that improved oil recoveries are obtained 6 with increased n-amyl alcohol concentrations. That is, as .~ ~ 7 the alcohol concentration is increased to a point where the 8 micellar dispersion solubilizes about equal volumes of the 9 crude oil and the connate water, improved oil recoveries are realized.
- 1' PREFERRED EMBODIMENTS OF THE INVENTION
13 The term "micellar dispersion" as used herein is meant 14 to include micellar solutions, microemulsions, "transparent emulsion", hydrous soluble oils, micellar systems containing 16 lamellar micelles, etc. These systems can be oil-external or 17 water-external, they can act like they are either oil-external 18 or water-external or both, and they can al50 be in an "inter-19 mediate region" between a "classically" oil-external micellar system and a "classically" water-external micellar system.
21 However, all of the systems, regardless of the externality 22 properties, are thermodynamically stable and optically 23 clear; however, color bodies within the different components 24 can prevent the transmission of light.
The micellar dispersions are composed of hydrocarbon, 26 water, petroleum sulfonate, cosurfactant, and optionally 27 electrolyte. Additional component(s) can be added ~o 28 impart desired properties to the micellar dispersion.
29 However, these components must be compatible with the other components of the dispersion and not impart adverse properties 31 to the system.
!1 ~4~
iO6S041 1 Examples of the components us~ful with the micellar 2 dispersion are defined within the patents mentioned in the 3 "Description of the Prior Art".
4 The surfactant can be anionic, nonionic, or cationic, or mixtures thereof. Preferably, it is a monovalent cation-6 containing petroleum sulfonate obtained by sulfonating a fraction of crude oil, e.g. gas oil, or whole or topped `
8 crude oil. Desirably, the petroleum sulfonate has an 9 average equivalent weight within the range of about 350 to about 525 and more preferably about 390 to about 470 and 11 most preferably about 400 to about 470. The petroleum 12 sulfonate can contain unreacted hydrocarbon and salts (here-13 inafter defined as electrolytes).
14 The hydrocarbon is typically crude oil, a fraction thereof, unreacted vehicle oil within the surfactant, 16 synthesized hydrocarbon, mixtures thereof, or like materials.
17 Water within the micellar dispersion can be distilled 18 water, fresh water, or water containing a moderate amount of 19 salts. Typically, the water contains about 5 to about 50,000 ppm of TDS (total dissolved solids). Preferably, the 21 water does not contain sufficient amounts of multi-valent 22 cations to displace or exchange a significant amount of the 23 cations on the surfactant. -Useful electrolytes include water-soluble inorganic salts, inorganic bases, inorganic acids, or mixtures thereof.
26 Typically, the salts are reaction by-products from the 27 preferred petroleum sulfonate, e.g. ammonium sulfate, ammonium 28 sulfite, sodium sulfate, sodium sulfite, etc. The electrolytes 29 can be added or blended with other electrolytes within the aqueous phase of the micellar dispersion mixture.
31 The cosurfactant, also known as a semi-polar organic 10~i~041 1 compound, cosolubilizer, stabilizing agent, etc., is an 2 or~anic compound~s) containing 1 to about 25 or more and 3 preferably about 3 to about 16 carbon atoms. It can be an 4 alcohol, amide, amino compound, ester, aldehyde, ketone, complexes thereof, or a compound containing one or more of 6 amido, hydroxy, bromo, chloro, carbonato, mercapto, oxo, 7 oxy, carbonyl, or like groups, or mixtures thereof. Specific 8 examples incl~de isopropanol, butanol, amyl alcohols, 9 hexanols, octanols, decyl alcohols, alkyl aryl alcohols such as n-nonyl phenol and p-nonyl phenol, 2-buto~yhexanol, 11 alcoholic liquors such as fusel oil, mixed isomers of primary 12 amyl or hexyl alcohols (Alfol alcohols, marketed by Continental 13 Oil Company, ethoxylated alcohols such as alcohols containing 14 about 4 to about 16 carbon atoms that are ethoxylated and optionally sulfated, hydrogenated hydrocarbons such as 16 hydrogenated croton oil, amidized hydrocarbons, and like 17 materials. The preferred cosurfactant is an alcohol which 18 can be primary, secondary or tertiary alcohol or mixtures 19 thereof and can optionally be ethoxylated and/or sulfated.
2~ Concentration of the components within the micellar 21 dispersion vary depending upon the particular component and 22 the particular properties desired of the micellar dispersion.
23 Typically, the concentration is about 4 to about 86% and 24 preferably about 5 to about 50% and more preferably about 6 25 to about 20~ hydrocarbon, about 10 to about 92% and preferably 26 about 40 to about 91~ and more preferably about 60 to about' 27 90% water, about 4 to about 20% or more and preferably about 28 6 to about 16 and more preferably about 7 to about 12% of 29 surfactant, about 0.01 to about 20% and preferably about 30 0.05 to about 10% and more preferably about 0.1 to about 1%
31 of cosurfactant, and about 0.001 to about 10% and preferably .
Il 106~0~
1 about 0.01 to about 7.5% and more preferably about 0.1 to 2 about 5~ of electrolyte. ~
3 The micellar dispersion is injected into the formation 4 in volume amounts of 1 to about 50% or more, and preferably
7 Gogarty teaches in U.S, 3,493,051 improved flooding by 8 incorporating alkali metal hydroxide into the micellar 9 dispersion to make the dispersion more hydrophilic.
U.S. 3,507,331 and 3,520,365 to Jones define an im-11 proved method of designing the flooding system to impart 12 stability to the micellar dispersion.
13 Healy et al in "Physical Chemical Aspects of Micro-14 emulsion Flooding", Society of Petroleum Engineers ~ournal, 14 (5), Page 491, October, 1974, teaches optimization of a 16 microemulsion for oil recovery is obtained by adjusting the 17 electrolyte concentration to "optimal salinity".
18 Design of micellar systems for improved oil recovery is 19 usually effected with petroleum sulfonates, hydrocarbon, water, electrolyte, and one or more alcohols as the co-21 surfactants. Often, the choice of petroleum sulfonate, 22 is limited and may not be the optimum one for the connate 23 water and/or crude oil within the reservoir. As a result, 24 oil recoveries are generally lower than that desired if a more desirable surfactant could be used.
26 If the micellar dispersion is improperly constituted 27 such that it solubilizes a considerably larger volume of 28 connate water than it solubilizes crude oil, the high amount 29 of water take-up dilutes the surfactant concentration and reduces the micellar dispersion's ability to solubilize crude 31 oil--in some cases to zero. In such cases, the micellar dis-,, ;, .
. ~, ~ , . . . . : .
. , ~ .
10~04~ ~
iOIl lo~e. Lts al)iliLy to disl)lncc cru(le oil at residual oil saturation and the oil recovery eff:icicncy is reduced.
On the otller hand, a micellar dispersion can be improperly designe~ to solubllize large amounts of crude oil, but little or no water. Again, oil recovery efficiency suffers because, although the micellar dispersion can readily displace crude oil from a reservoir rock, the aqueous mobility buffer and drive fluids are incapable of "miscibly" displacing the micellar dispersion; the latter can be left in the rock since its mobility 10 is reduced.
SUMMARY OF THE IN~E~TION
-Applicant has discovered that optimum oil recovery is obtained by designing the micellar dispersion to solubilize about equal volumes of connate water and the crude oil ~hydrocarbon) within the reservoir. This solubility characteristic is controlled, to a large degree, by selection of the proper type and concentration of cosurfactant used to prepare the micellar dispersion. Such a j selection is obtained from data resulting from solubilizing different amounts of connate water and crude oil at different 20 cosurfactant concentrations. The cosurfactant concentration at < which the solubilization or uptake of the hydrocarbon and connate . water is about equal, is the preferred design of the micellar dispersion to obtain maximum oil recovery.
In one particular aspect the present invention ~, provides in a process for recovering crude oil from a subterranean formation wherein a micellar dispersion comprised of water, hydro-carbon, surfactant, cosurfactant, and inorganic electrolyte is ~r, injected into the formation to displace crude oil therefrom, the improvement comprising injecting into the formation a micellar 30 dispersion which solubilizes substantially equal volumes of crude eon~e ' ~ oil and~water.
In another particular aspect the present inventlon jl/ ~- ~ -3-., ~ .
.
106t~041 ~ovi(l~ s l-ro(~ ; For ro(~ovorin~ crll(le oi1 From a .~uhterranean forma~iol1 w~rcin ~1 n~ ellar dispersiol1 con~pris:ing water, hydrocarbvn surfactant, cosurf~ctant, and inorgan:l.c ~l.ectrolyte is i.njected into the ~or~ation to displace crude oil Lherefrom, the .improvement comprlslng designing the miccl.lar dispers:ior1 to soluh.l.lize ~ ~ 0,7~l f ~
substant:i.al.1.y equal volumes o~ crude oil and ~ water and thereafter injecting the micellar dispers.ion into the formation and displacing it therethrough to recover crude oil.
In yet a Eurther particular aspect the present l0 invention provides in a process for recovering crude oil from a subterranean formation wherein a micellar dispersion comp~ising water, hydrocarbon, surfactant, inorganic electrolyte, and co-surfactant is injected into the formation followed by an aqueous mobility buffer to displace crude oil therefrom, the improvement comprising formulating the micellar dispersion to solubilize substantially equal volumes of the crude oil within the subterranean Ca~af e formation and thc water within the aqueous mobility buffer and , thereafter injecting the micellar dispersion and the aqueous mobility buffer into the subterranean formation to displace crude oil 20 therefrom.
BRIEF DESCRIPTION OF THE DRAWINGS
O Figure l represents the amount of connate water and crude oil that is solubilized by a micellar dispersion at different :
cosurfactant concentrations. The micellar dispersion composition ~ -is defined in E~ample I. At the junc-.
-.. .
jl/ .......................... -3a-~ .
,, 10~0~
7 ture of the connate water and crud~ oil uptake is the optimum 2 concentration of the cosurfactant for this particular system.
3 Figure 2 represents the percent oil recovery of a 4 micellar dispersion composition defined in Example II. The curves illustrate that improved oil recoveries are obtained 6 with increased n-amyl alcohol concentrations. That is, as .~ ~ 7 the alcohol concentration is increased to a point where the 8 micellar dispersion solubilizes about equal volumes of the 9 crude oil and the connate water, improved oil recoveries are realized.
- 1' PREFERRED EMBODIMENTS OF THE INVENTION
13 The term "micellar dispersion" as used herein is meant 14 to include micellar solutions, microemulsions, "transparent emulsion", hydrous soluble oils, micellar systems containing 16 lamellar micelles, etc. These systems can be oil-external or 17 water-external, they can act like they are either oil-external 18 or water-external or both, and they can al50 be in an "inter-19 mediate region" between a "classically" oil-external micellar system and a "classically" water-external micellar system.
21 However, all of the systems, regardless of the externality 22 properties, are thermodynamically stable and optically 23 clear; however, color bodies within the different components 24 can prevent the transmission of light.
The micellar dispersions are composed of hydrocarbon, 26 water, petroleum sulfonate, cosurfactant, and optionally 27 electrolyte. Additional component(s) can be added ~o 28 impart desired properties to the micellar dispersion.
29 However, these components must be compatible with the other components of the dispersion and not impart adverse properties 31 to the system.
!1 ~4~
iO6S041 1 Examples of the components us~ful with the micellar 2 dispersion are defined within the patents mentioned in the 3 "Description of the Prior Art".
4 The surfactant can be anionic, nonionic, or cationic, or mixtures thereof. Preferably, it is a monovalent cation-6 containing petroleum sulfonate obtained by sulfonating a fraction of crude oil, e.g. gas oil, or whole or topped `
8 crude oil. Desirably, the petroleum sulfonate has an 9 average equivalent weight within the range of about 350 to about 525 and more preferably about 390 to about 470 and 11 most preferably about 400 to about 470. The petroleum 12 sulfonate can contain unreacted hydrocarbon and salts (here-13 inafter defined as electrolytes).
14 The hydrocarbon is typically crude oil, a fraction thereof, unreacted vehicle oil within the surfactant, 16 synthesized hydrocarbon, mixtures thereof, or like materials.
17 Water within the micellar dispersion can be distilled 18 water, fresh water, or water containing a moderate amount of 19 salts. Typically, the water contains about 5 to about 50,000 ppm of TDS (total dissolved solids). Preferably, the 21 water does not contain sufficient amounts of multi-valent 22 cations to displace or exchange a significant amount of the 23 cations on the surfactant. -Useful electrolytes include water-soluble inorganic salts, inorganic bases, inorganic acids, or mixtures thereof.
26 Typically, the salts are reaction by-products from the 27 preferred petroleum sulfonate, e.g. ammonium sulfate, ammonium 28 sulfite, sodium sulfate, sodium sulfite, etc. The electrolytes 29 can be added or blended with other electrolytes within the aqueous phase of the micellar dispersion mixture.
31 The cosurfactant, also known as a semi-polar organic 10~i~041 1 compound, cosolubilizer, stabilizing agent, etc., is an 2 or~anic compound~s) containing 1 to about 25 or more and 3 preferably about 3 to about 16 carbon atoms. It can be an 4 alcohol, amide, amino compound, ester, aldehyde, ketone, complexes thereof, or a compound containing one or more of 6 amido, hydroxy, bromo, chloro, carbonato, mercapto, oxo, 7 oxy, carbonyl, or like groups, or mixtures thereof. Specific 8 examples incl~de isopropanol, butanol, amyl alcohols, 9 hexanols, octanols, decyl alcohols, alkyl aryl alcohols such as n-nonyl phenol and p-nonyl phenol, 2-buto~yhexanol, 11 alcoholic liquors such as fusel oil, mixed isomers of primary 12 amyl or hexyl alcohols (Alfol alcohols, marketed by Continental 13 Oil Company, ethoxylated alcohols such as alcohols containing 14 about 4 to about 16 carbon atoms that are ethoxylated and optionally sulfated, hydrogenated hydrocarbons such as 16 hydrogenated croton oil, amidized hydrocarbons, and like 17 materials. The preferred cosurfactant is an alcohol which 18 can be primary, secondary or tertiary alcohol or mixtures 19 thereof and can optionally be ethoxylated and/or sulfated.
2~ Concentration of the components within the micellar 21 dispersion vary depending upon the particular component and 22 the particular properties desired of the micellar dispersion.
23 Typically, the concentration is about 4 to about 86% and 24 preferably about 5 to about 50% and more preferably about 6 25 to about 20~ hydrocarbon, about 10 to about 92% and preferably 26 about 40 to about 91~ and more preferably about 60 to about' 27 90% water, about 4 to about 20% or more and preferably about 28 6 to about 16 and more preferably about 7 to about 12% of 29 surfactant, about 0.01 to about 20% and preferably about 30 0.05 to about 10% and more preferably about 0.1 to about 1%
31 of cosurfactant, and about 0.001 to about 10% and preferably .
Il 106~0~
1 about 0.01 to about 7.5% and more preferably about 0.1 to 2 about 5~ of electrolyte. ~
3 The micellar dispersion is injected into the formation 4 in volume amounts of 1 to about 50% or more, and preferably
5 about 4 to about 15~ FPV (formation pore volume). This is
6 preferably followed by a mobility buffer, preerably an ~; 7 aqueous solution containing a water-soluble polymer which 8 imparts permeability reduction to the formation and/or viscosity increasing properties to the aqueous solution--10 examples of volume amounts include about 10 to about 200%
11 FPV or more and preferably about 50 to about 150~ FPV, and 12 more preferably about 70 to about 100% FPV. A water drive ~; 13 is injected to displace the micellar dispersion and the 1 mobility buffer toward a productlon well in fluid communication 5 with the formation to recover crude oil through said production 16 well.
17 The cosurfactant used to make up the micellar dis-18 ~ persion must permit the micellar dispersion to solubilize 19 substantially equal volumes of the crude oil and the connate ~ 20 water within the subterranean reservoir. That is, the ,"r 21 properties of the connate water as well as the crude oil 22 must be compatible with the micellar dispersion such that 23 the latter will be permitted to solubilize equal volumes ~ 24 thereof. The cosurfactant must impart a property to the 25 micellar dispersion such that it will not be substantially 26 hydrophilic or substantially oleophilic, if either is the 27 case, then the oil recoveries will be adversely influenced.
.2 ~ 28 Determining the desired cosurfactant needed for the 29 particular micellar dispersion will require routine experi-~' 30 mentation. Such can be effected by obtaining samples of the ' 31 crude oil and the connate water, mixing them separately with ;. E
~ 750022-A -7-,.... ..
~, ,.,, , . ~ . . . .
~,.................. . .
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1 cosurfactant-free micellar dispersion and thereafter adding 2 different quantities of suspected cosurf~ctants desired for 3 the system and obtaining solubilization data. At the 4 juncture of the crude oil uptake and connate water uptake, for example see Figure 1, is the desired concentration of 6 the particular cosurfactant for the particular micellar dis-
11 FPV or more and preferably about 50 to about 150~ FPV, and 12 more preferably about 70 to about 100% FPV. A water drive ~; 13 is injected to displace the micellar dispersion and the 1 mobility buffer toward a productlon well in fluid communication 5 with the formation to recover crude oil through said production 16 well.
17 The cosurfactant used to make up the micellar dis-18 ~ persion must permit the micellar dispersion to solubilize 19 substantially equal volumes of the crude oil and the connate ~ 20 water within the subterranean reservoir. That is, the ,"r 21 properties of the connate water as well as the crude oil 22 must be compatible with the micellar dispersion such that 23 the latter will be permitted to solubilize equal volumes ~ 24 thereof. The cosurfactant must impart a property to the 25 micellar dispersion such that it will not be substantially 26 hydrophilic or substantially oleophilic, if either is the 27 case, then the oil recoveries will be adversely influenced.
.2 ~ 28 Determining the desired cosurfactant needed for the 29 particular micellar dispersion will require routine experi-~' 30 mentation. Such can be effected by obtaining samples of the ' 31 crude oil and the connate water, mixing them separately with ;. E
~ 750022-A -7-,.... ..
~, ,.,, , . ~ . . . .
~,.................. . .
106604~
1 cosurfactant-free micellar dispersion and thereafter adding 2 different quantities of suspected cosurf~ctants desired for 3 the system and obtaining solubilization data. At the 4 juncture of the crude oil uptake and connate water uptake, for example see Figure 1, is the desired concentration of 6 the particular cosurfactant for the particular micellar dis-
7 persion/crude oil/connate water system. This method permits one to design a micellar dispersion particularly suited for 9 a particular reservoir. The type of cosurfactant, e.g. HLB
(hydrophil-lipophil balance) and concentration thereof, will 11 influence the desired viscosity of the micellar dispersion;
12 thus, this also has to be considered with designing the 13 optimum solubility properties of the micellar dispersion.
14 The cosurfactant concentration in the micellar dis-persion is preferably on the "right side" of the viscosity 16 maximum which results from titrating with a cosurfactant a 17 micellar dispersion-free cosurfactant mixture containin~
18 ¦ greater than about 60% water. That is, upon cosurfactant 19 titration, the dispersion mixture generally goes through a viscosity maximum and thereafter the viscosity decreases.
21 The "right side" is past this viscosity maximum. A micellar 22 dispersion containing less than about 60~ water may not pass 23 through a viscosity maximum upon cosurfactant titration but 24 instead may pass through a minimum viscosity--if this is the case it is preferred that the system be at the minimum vis-26 cosity or to the "right side" of the viscosity curve to obtain 27 optimum oil recovery.
28 For this invention, the cosurfactant concentration is 29 increased or the titration continued until the concentration is sufficient to permit the micellar dispersion to solubilize 31 about equal amounts of the connate water and the crude oil.
'I , :
i~ O41 1 of course, the desired viscosity of the micellar dispersion 2 will depend upon the combined mobi-lity of the crude oil and 3 the connate water within the formation, the design mobility 4 of the mobility buffer which is injected after the micellar dispersion, the "life" of the flooding project, and in 6 general, the overall design mobility and desired "payout"
7 and economics of the flooding project.
(hydrophil-lipophil balance) and concentration thereof, will 11 influence the desired viscosity of the micellar dispersion;
12 thus, this also has to be considered with designing the 13 optimum solubility properties of the micellar dispersion.
14 The cosurfactant concentration in the micellar dis-persion is preferably on the "right side" of the viscosity 16 maximum which results from titrating with a cosurfactant a 17 micellar dispersion-free cosurfactant mixture containin~
18 ¦ greater than about 60% water. That is, upon cosurfactant 19 titration, the dispersion mixture generally goes through a viscosity maximum and thereafter the viscosity decreases.
21 The "right side" is past this viscosity maximum. A micellar 22 dispersion containing less than about 60~ water may not pass 23 through a viscosity maximum upon cosurfactant titration but 24 instead may pass through a minimum viscosity--if this is the case it is preferred that the system be at the minimum vis-26 cosity or to the "right side" of the viscosity curve to obtain 27 optimum oil recovery.
28 For this invention, the cosurfactant concentration is 29 increased or the titration continued until the concentration is sufficient to permit the micellar dispersion to solubilize 31 about equal amounts of the connate water and the crude oil.
'I , :
i~ O41 1 of course, the desired viscosity of the micellar dispersion 2 will depend upon the combined mobi-lity of the crude oil and 3 the connate water within the formation, the design mobility 4 of the mobility buffer which is injected after the micellar dispersion, the "life" of the flooding project, and in 6 general, the overall design mobility and desired "payout"
7 and economics of the flooding project.
8 The following examples are presented to teach specific
9 embodiments of the invention~ Unless otherwise specified, all percents are based on volume and all measurements are 11 made at ambient temperature, i.e. 22-23C.
13 A micellar dispersion mixture is obtained by mixing 14 ll.7% of an ammonium petroleum sulfonate having an average equivalent weight of 420 and being 62 weight percent active 16 and obtained by sulfonating a heavy vacuum gas oil with SO3, 17 22.8% of a crude oil having viscosity of 7-9 cp. and 37 API
18 gravity and identified as "Illinois Crude"; 65.5% water 19 containing 400 ppm of TDS and lO, oon ppm of ammonium sulfate (does not include water within the petroleum sulfonate--when 21 the latter water is included, the miceliar dispersion contains 22 70.0% water by weight).
23 Figure l illustrates the solubilization behavior of the 24 resulting micellar dispersion upon the addition of n-hexanol, a relatively water-insoluble alcohol. The crude oil is 26 "Illinois Crude" and the brine or connate water contains 27 lO,000 ppm of ammonium sulfate. Below an n-hexanol concen-28 tration of 0.43 ml/lO0 ml alcohol-free micellar dispersion, 29 the system rejects the crude oil. For example, at a concentratio of 0.4 ml of n-hexanol/lO0 ml of alcohol-free micellar 31 dispersion, the dispersion is in equilibrium with a layer of 750022-A -9~
. I
1~ 106~041 1 ¦ crude oil. As the n-hexanol concentration is increased, the 2 1 micellar dispersion solubilizes the crude oil and the crude 3 ¦ oil layer disappears, i.e. the system becomes a single phase 4 ¦ at an n-hexanol concentration of 0.44. The single phase 5 1 region is present over an n-hexanol concentration of 0.44 to .
¦ 0.93 ml but after the 0.93 concentration, the system expels 7 an aqueous phase. Thus, within the single phase region, this composition has the capacity to solubilize increasing 9 amounts of crude oil with increasing n-hexanol concentra-tion, but its capacity to solubilize the brine decreases, 11 from an initially high value at the lower limit of the 12 cosurfactant concentration down to zero at the 0.93 ml of n-13 hexanol. It is.apparent from this graph that the micellar 14 dispersion slug's capacity for solubilizing brine and crude .
15 oil is controlled by the cosurfactant concentration. .
16 At the ~uncture of the brine and crude oil uptake is 17 the optimum concentration of the n-hexanol for this dispersion 18 to obtain maximum oil recovery. :
19 . . EXAMPLE II .
A micellar dispersion mixture is obtained by mixing 10%
21 of an.ammonium petroleum sulfonate having an average equiva-22 lent weight of 440 and being 61 weight percent active 23 sulfonate and obtained by sulfonating a vacuum gas.oil with `
24 sulfuric acid. 40% of the crude oil defined in Example I, and 50% of water containing 400 ppm of TDS. The total water 26 concentration of the mixture including water from the 27 petroleum sulfonate is 54.5%. This total water contains 28 3900 ppm of ammonium sulfate, initially contained within the .
29 petroleum sulfonate. To this mixtuxe there iæ added different amounts of n-amyl alcohol, 1% FPV and 5%.FPV micellar dispersions 31 containing different concentrations of the n-amyl alcohol 750022-A -lO-.. , ,.~.~ , ~.
ll 10titi041 1 followed by a mobility buffer are flooded in 3 inch diameter 2 48 inch long cores. The cores, before flooding, are placed 3 in a tertiary condition by first flooding with water containing 4 6000 ppm of TDS, thereafter they are flooded with the crude oil identified in Example I until irreducible water saturation 6 and thereafter the cores are flooded with water containing 7 6000 ppm of TDS to irreducible oil saturation. The percent oil recovery of each of the floods is iLlustrated in Figure 9 2. AS is evident from this figure, increased concentrations , of the alcohol permit higher oil recoveries of the micellar 11 dispersion. With this particular system, at the high con-12 centrations of alcohol, the micellar dispersion solubilizes 13 about equal volumes of the crude oil and the connate water 14 within the cores~
It is not intended that the above examples limit the 16 invention. Rather, it is intended that all equivalents 17 obvious to those skilled in the art be incorporated within ' 18 the scope of the invention as defined within the speci-2D ~ Ati~ and appended clai~s, .,
13 A micellar dispersion mixture is obtained by mixing 14 ll.7% of an ammonium petroleum sulfonate having an average equivalent weight of 420 and being 62 weight percent active 16 and obtained by sulfonating a heavy vacuum gas oil with SO3, 17 22.8% of a crude oil having viscosity of 7-9 cp. and 37 API
18 gravity and identified as "Illinois Crude"; 65.5% water 19 containing 400 ppm of TDS and lO, oon ppm of ammonium sulfate (does not include water within the petroleum sulfonate--when 21 the latter water is included, the miceliar dispersion contains 22 70.0% water by weight).
23 Figure l illustrates the solubilization behavior of the 24 resulting micellar dispersion upon the addition of n-hexanol, a relatively water-insoluble alcohol. The crude oil is 26 "Illinois Crude" and the brine or connate water contains 27 lO,000 ppm of ammonium sulfate. Below an n-hexanol concen-28 tration of 0.43 ml/lO0 ml alcohol-free micellar dispersion, 29 the system rejects the crude oil. For example, at a concentratio of 0.4 ml of n-hexanol/lO0 ml of alcohol-free micellar 31 dispersion, the dispersion is in equilibrium with a layer of 750022-A -9~
. I
1~ 106~041 1 ¦ crude oil. As the n-hexanol concentration is increased, the 2 1 micellar dispersion solubilizes the crude oil and the crude 3 ¦ oil layer disappears, i.e. the system becomes a single phase 4 ¦ at an n-hexanol concentration of 0.44. The single phase 5 1 region is present over an n-hexanol concentration of 0.44 to .
¦ 0.93 ml but after the 0.93 concentration, the system expels 7 an aqueous phase. Thus, within the single phase region, this composition has the capacity to solubilize increasing 9 amounts of crude oil with increasing n-hexanol concentra-tion, but its capacity to solubilize the brine decreases, 11 from an initially high value at the lower limit of the 12 cosurfactant concentration down to zero at the 0.93 ml of n-13 hexanol. It is.apparent from this graph that the micellar 14 dispersion slug's capacity for solubilizing brine and crude .
15 oil is controlled by the cosurfactant concentration. .
16 At the ~uncture of the brine and crude oil uptake is 17 the optimum concentration of the n-hexanol for this dispersion 18 to obtain maximum oil recovery. :
19 . . EXAMPLE II .
A micellar dispersion mixture is obtained by mixing 10%
21 of an.ammonium petroleum sulfonate having an average equiva-22 lent weight of 440 and being 61 weight percent active 23 sulfonate and obtained by sulfonating a vacuum gas.oil with `
24 sulfuric acid. 40% of the crude oil defined in Example I, and 50% of water containing 400 ppm of TDS. The total water 26 concentration of the mixture including water from the 27 petroleum sulfonate is 54.5%. This total water contains 28 3900 ppm of ammonium sulfate, initially contained within the .
29 petroleum sulfonate. To this mixtuxe there iæ added different amounts of n-amyl alcohol, 1% FPV and 5%.FPV micellar dispersions 31 containing different concentrations of the n-amyl alcohol 750022-A -lO-.. , ,.~.~ , ~.
ll 10titi041 1 followed by a mobility buffer are flooded in 3 inch diameter 2 48 inch long cores. The cores, before flooding, are placed 3 in a tertiary condition by first flooding with water containing 4 6000 ppm of TDS, thereafter they are flooded with the crude oil identified in Example I until irreducible water saturation 6 and thereafter the cores are flooded with water containing 7 6000 ppm of TDS to irreducible oil saturation. The percent oil recovery of each of the floods is iLlustrated in Figure 9 2. AS is evident from this figure, increased concentrations , of the alcohol permit higher oil recoveries of the micellar 11 dispersion. With this particular system, at the high con-12 centrations of alcohol, the micellar dispersion solubilizes 13 about equal volumes of the crude oil and the connate water 14 within the cores~
It is not intended that the above examples limit the 16 invention. Rather, it is intended that all equivalents 17 obvious to those skilled in the art be incorporated within ' 18 the scope of the invention as defined within the speci-2D ~ Ati~ and appended clai~s, .,
Claims (7)
PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. In a process for recovering crude oil from a subterranean formation wherein a micellar dispersion comprised of water, hydrocarbon, surfactant, cosurfactant, and inorganic electrolyte is injected into the formation to displace crude oil therefrom, the improvement comprising injecting into the formation a micellar dispersion which solubilizes substantially equal volumes of crude oil and connate water.
2. The process of Claim 1 wherein the water solubilized by the micellar dispersion is the same as water within an aqueous mobility buffer that is injected behind the micellar dispersion.
3. In a process for recovering crude oil from a subterranean formation wherein a micellar dispersion comprising water, hydrocarbon, surfactant, cosurfactant, and inorganic electrolyte is injected into the formation to displace crude oil therefrom, the improvement comprising designing the micellar dispersion to solubilize substantially equal volumes of crude oil and connate water and thereafter injecting the micellar dispersion into the formation and displacing it therethrough to recover crude oil.
4. The process of Claim 3 wherein the solubilized water is the same as the water within an aqueous mobility buffer that is injected behind the micellar dispersion.
5. The process of Claim 3 wherein a cosurfactant within the micellar dispersion is preselected to obtain the desired solubilization properties of the micellar dispersion.
6. The process of Claim 3 wherein a cosurfactant is added to a micellar dispersion already containing a cosurfactant to obtain the desired solubilization properties of the micellar dispersion.
7. In a process for recovering crude oil from a subterranean formation wherein a micellar dispersion comprising water, hydrocarbon, surfactant, inorganic electrolyte, and co-surfactant is injected into the formation followed by an aqueous mobility buffer to displace crude oil therefrom, the improvement comprising formulating the micellar dispersion to solubilize substantially equal volumes of the crude oil within the subterranean formation and connate water within the aqueous mobility buffer and thereafter injecting the micellar dispersion and the aqueous mobility buffer into the subterranean formation to displace crude oil therefrom.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US60356075A | 1975-08-11 | 1975-08-11 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1066041A true CA1066041A (en) | 1979-11-13 |
Family
ID=24415960
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA255,604A Expired CA1066041A (en) | 1975-08-11 | 1976-06-24 | Flooding with micellar systems to solubilize equal volumes of hydrocarbon and water |
Country Status (11)
| Country | Link |
|---|---|
| JP (1) | JPS5222502A (en) |
| AU (1) | AU1677376A (en) |
| BR (1) | BR7604819A (en) |
| CA (1) | CA1066041A (en) |
| DE (1) | DE2628526C3 (en) |
| EG (1) | EG12326A (en) |
| FR (1) | FR2321036A1 (en) |
| GB (1) | GB1520564A (en) |
| IN (1) | IN145457B (en) |
| NL (1) | NL7608930A (en) |
| RO (1) | RO84314B (en) |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| AR205218A1 (en) * | 1975-01-20 | 1976-04-12 | Mc Graw Edison Co | IMPROVED ELECTRICAL CAPACITOR AND MANUFACTURING METHOD |
| JPS576249B2 (en) * | 1975-01-22 | 1982-02-04 |
-
1976
- 1976-06-18 IN IN1082/CAL/76A patent/IN145457B/en unknown
- 1976-06-22 GB GB25905/76A patent/GB1520564A/en not_active Expired
- 1976-06-24 DE DE2628526A patent/DE2628526C3/en not_active Expired
- 1976-06-24 CA CA255,604A patent/CA1066041A/en not_active Expired
- 1976-07-16 JP JP51084062A patent/JPS5222502A/en active Granted
- 1976-07-23 BR BR7604819A patent/BR7604819A/en unknown
- 1976-08-06 FR FR7624048A patent/FR2321036A1/en not_active Withdrawn
- 1976-08-07 EG EG480/76A patent/EG12326A/en active
- 1976-08-10 RO RO87265A patent/RO84314B/en unknown
- 1976-08-11 AU AU16773/76A patent/AU1677376A/en not_active Expired
- 1976-08-11 NL NL7608930A patent/NL7608930A/en not_active Application Discontinuation
Also Published As
| Publication number | Publication date |
|---|---|
| AU1677376A (en) | 1978-02-16 |
| IN145457B (en) | 1978-10-14 |
| DE2628526A1 (en) | 1977-02-24 |
| BR7604819A (en) | 1977-08-02 |
| GB1520564A (en) | 1978-08-09 |
| RO84314A (en) | 1984-05-23 |
| DE2628526B2 (en) | 1979-05-17 |
| DE2628526C3 (en) | 1980-01-17 |
| RO84314B (en) | 1984-07-30 |
| EG12326A (en) | 1978-09-30 |
| FR2321036A1 (en) | 1977-03-11 |
| NL7608930A (en) | 1977-02-15 |
| JPS562595B2 (en) | 1981-01-20 |
| JPS5222502A (en) | 1977-02-19 |
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