US4360061A — Oil recovery process using polymer microemulsion …

Claim 1

Independent Claim 167 words

A process for recovering crude oil from a subterranean formation which comprises injecting into the formation a stabilized microemulsion system which contains a polymer-microemulsion complex in an amount effective to displace oil, said microemulsion system comprising (a) a microemulsion containing as components (1) an oil, (2) water having up to 25% by weight of dissolved inorganic salts, and (3) 0.2 to 15 wt. %, based on the microemulsion, of at least one anionic surfactant balanced to form the microemulsion, and (b) from 0.1 to 10% by weight, based on the microemulsion of a polar polymer capable of forming a polymer-microemulsion complex wherein the polar polymer has a molecular weight of from 4,000 to 5,000,000 and is selected from the group consisting of branched polyethylene oxide condensation product of polyethylene oxide, bisphenol A and epichlorohydrin and polyvinyl pyrrolidone, the polymer-microemulsion complex being characterized by a complexation energy of at least 2 Kcal/mole, driving the microemulsion system through the formation to displace oil, and recovering the resultant crude oil.

Claim 2

Dependent Claim 167 words

A process for recovering crude oil from a subterranean formation which comprises injecting into the formation a stabilized microemulsion system which contains a polymer-microemulsion complex in an amount effective to displace oil, said microemulsion system comprising (a) a microemulsion containing as components (1) an oil, (2) water having up to 25% by weight of dissolved inorganic salts, and (3) 0.2 to 15 wt. %, based on the microemulsion, of at least one anionic surfactant balanced to form the microemulsion, and (b) from 0.1 to 10% by weight, based on the microemulsion of a polar polymer capable of forming a polymer-microemulsion complex wherein the polar polymer has a molecular weight of from 4,000 to 5,000,000 and is selected from the group consisting of branched polyethylene oxide condensation product of polyethylene oxide, bisphenol A and epichlorohydrin and polyvinyl pyrrolidone, the polymer-microemulsion complex being characterized by a complexation energy of at least 2 Kcal/mole, driving the microemulsion system through the formation to displace oil, and recovering the resultant crude oil.

Claim 3

Dependent Claim 29 words

The process of claim 1 wherein the microemulsion contains from 0.3 to 98 wt.% component (1), 1 to 99 wt.% component (2), and 0.2 to 15 wt.% component (3).

Claim 4

Dependent Claim 16 words

The process of claim 1 wherein the complexation energy is from about 5 to 15 Kcal/mole.

Claim 5

Dependent Claim 22 words

The process of claim 1 wherein component (2) contains from about 1 to 14 wt.% based on water of dissolved inorganic salts.

Claim 6

Dependent Claim 56 words

The process of claim 1 wherein component (1) is a sweet or sour crude; synthetic crude; refined fraction such as kerosene, diesel oil, lube oil, aromatic naphtha or white oil boiling at from 80° to 345° C.; C 6 to C 22 aliphatic hydrocarbon; aromatic hydrocarbon boiling at from 80° to 300° C.; or mixtures thereof.

Claim 7

Dependent Claim 25 words

The process of claim 1 wherein component (3) is a mixture of an anionic surfactant with at least one other anionic, nonionic or cationic surfactant.

Claim 8

Dependent Claim 16 words

The process of claim 6 wherein the anionic surfactant or cosurfactant is a sulfonate or sulfate.

Claim 9

Dependent Claim 94 words

The process of claim 7 wherein the sulfonate has the formula [R.sup.1 --SO.sub.3 ].sup.⊕ Y.sup.⊖ where R 1 is C 8 to C 25 aliphatic, C 14 to C 36 alkylaryl or R 2 --(OCH 2 CH 2 ) n where R 2 is the same as R 1 and n is an integer from 1 to 60, and Y is hydrogen, alkali metal cation or N(R 3 ) 4 .sup.⊕ where each R 3 is independently hydrogen, alkyl of 1 to 4 carbon atoms or hydroxy alkyl of 1 to 4 carbon atoms.

Claim 10

Dependent Claim 95 words

The process of claim 7 wherein the sulfate has the formula [R.sup.4 --O--SO.sub.3 ].sup.⊖ Y.sup.⊕ where R 4 is C 8 to C 25 aliphatic, C 14 to C 38 alkylaryl or R 5 --(OCH 2 CH 2 ) n where R 5 has the same definition as R 4 and n is an integer from 1 to 60, and Y is hydrogen, alkali metal cation or N(R 3 ) 4 .sup.⊕ where each R 3 is independently hydrogen, alkyl of 1 to 4 carbon atoms or hydroxy alkyl of 1 to 4 carbon atoms.

Claim 11

Dependent Claim 18 words

The process of claim 6 wherein the mixture contains dodecylxylene sulfonate or dodecylbenzene sulfonate as the anionic surfactant.

Claim 12

Dependent Claim 78 words

The process of claim 6 or 10 wherein the nonionic cosurfactant is an ethoxylated C 8 to C 25 alkanol or an ethoxylated phenol of the formula (R.sup.6).sub.r --A--[O(CH.sub.2 CH.sub.2 O).sub.p ].sub.q H where R 6 is C 1 to C 24 alkyl, A is benzene, P is 2 to 60, q is 1 or 2 and r is 1 to 5 with the proviso that when R is 1, R 6 is at least C 8 .

Claim 13

Dependent Claim 18 words

The process of claim 10 wherein the nonionic cosurfactant is an ethoxylated C 8 to C 24 alkylphenol.

Claim 14

Dependent Claim 27 words

The process of claim 12 wherein the nonionic cosurfactant is an ethoxylated octyl, -nonyl or -dodecyl phenol containing 8 to 24 --CH 2 CH 2 O-- groups.

Claim 15

Dependent Claim 28 words

The process of claim 10 wherein the anionic cosurfactant is a sulfated ethoxylated C 12 to C 16 alkanol or sulfonated ethoxylated C 8 to C 26 alkylphenol.

Claim 16

Dependent Claim 25 words

The process of claim 10 wherein the anionic cosurfactant is a sulfonated ethoxylated dinonyl phenol containing 8 to 50 --CH 2 CH 2 O-- groups.

Claim 17

Dependent Claim 35 words

The process of claim 6 or 10 wherein the nonionic or cationic cosurfactant is a C 8 to C 30 alkylamine, C 8 to C 30 ethoxylated alkylamine or the respective quaternary ammonium salts thereof.

Claim 18

Dependent Claim 32 words

The process of claim 10 wherein the nonionic or cationic cosurfactant has the formula ##STR14## where m is from 8 to 25 and the sum of u+v is from 2 to 20.

Claim 19

Dependent Claim 19 words

The process of claim 6 wherein the anionic surfactant and cosurfactant have hydrophilic and lipophilic properties which are balanced.

Claim 20

Dependent Claim 19 words

The process of claim 1 wherein the microemulsion is driven through the formation with a thickened water or brine.

Claim 21

Dependent Claim 13 words

The process of claim 1 wherein a cosolvent is incorporated into the microemulsion.

Claim 22

Dependent Claim 19 words

The process of claim 1 wherein the microemulsion system is injected as a 0.01 to 1.0 pore volume slug.

Claim 23

Dependent Claim 12 words

The process of claim 1 wherein the microemulsion is anisotropic and birefringent.

Claim 24

Dependent Claim 130 words

A process for recovering crude oil from a subterranean formation which comprises injecting into the formation an aqueous solution containing from 0.25 to 5 wt. % of a polar polymer having a molecular weight of from 4,000 to 5,000,000 and selected from the group consisting of branched polyethylene oxide condensation product of polyethylene oxide, bisphenol A and epichlorohydrin and polyvinyl pyrrolidone, a microemulsion containing an oil, water having up to 25 wt. % of dissolved inorganic salts and from 0.2 to 15 wt. % of at least one anionic surfactant balanced to form the microemulsion whereby a polymer-microemulsion complex is formed in-situ, said complex being characterized by a complexation energy of at least 2 Kcal/mole, driving the polymer-microemulsion complex through the formation to displace oil and recovering the resultant oil.

Claim 25

Dependent Claim 130 words

A process for recovering crude oil from a subterranean formation which comprises injecting into the formation an aqueous solution containing from 0.25 to 5 wt. % of a polar polymer having a molecular weight of from 4,000 to 5,000,000 and selected from the group consisting of branched polyethylene oxide condensation product of polyethylene oxide, bisphenol A and epichlorohydrin and polyvinyl pyrrolidone, a microemulsion containing an oil, water having up to 25 wt. % of dissolved inorganic salts and from 0.2 to 15 wt. % of at least one anionic surfactant balanced to form the microemulsion whereby a polymer-microemulsion complex is formed in-situ, said complex being characterized by a complexation energy of at least 2 Kcal/mole, driving the polymer-microemulsion complex through the formation to displace oil and recovering the resultant oil.

Claim 26

Dependent Claim 160 words

A process for recovering crude oil from a subterranean formation which comprises injecting into the formation a stabilized microemulsion system which contains a polymer-microemulsion complex in an amount effective to displace oil, said microemulsion system comprising (a) a microemulsion containing as components (1) an oil, (2) water having up to 25% by weight of dissolved inorganic salts, and (3) 0.2 to 15 wt. % based on the microemulsion of at least one anionic surfactant balanced to form the microemulsion, and (b) from 0.1 to 10% by weight, based on the microemulsion of a polar polymer capable of forming a polymer-microemulsion complex wherein the polar polymer is a branched polyethylene oxide condensation product of polyethylene oxide, bisphenol A and epichlorohydrin having a molecular weight of from 10,000 to 500,000, the polymer-microemulsion complex being characterized by a complexation energy of from about 5 to 15 Kcal/mole, driving the microemulsion system through the formation to displace oil, and recovering the resultant crude oil.

Claim 27

Dependent Claim 160 words

A process for recovering crude oil from a subterranean formation which comprises injecting into the formation a stabilized microemulsion system which contains a polymer-microemulsion complex in an amount effective to displace oil, said microemulsion system comprising (a) a microemulsion containing as components (1) an oil, (2) water having up to 25% by weight of dissolved inorganic salts, and (3) 0.2 to 15 wt. % based on the microemulsion of at least one anionic surfactant balanced to form the microemulsion, and (b) from 0.1 to 10% by weight, based on the microemulsion of a polar polymer capable of forming a polymer-microemulsion complex wherein the polar polymer is a branched polyethylene oxide condensation product of polyethylene oxide, bisphenol A and epichlorohydrin having a molecular weight of from 10,000 to 500,000, the polymer-microemulsion complex being characterized by a complexation energy of from about 5 to 15 Kcal/mole, driving the microemulsion system through the formation to displace oil, and recovering the resultant crude oil.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1985-11-22	1986-05-24	1986-11-23	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1989-11-22	1990-05-24	1990-11-23	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1993-11-22	1994-05-24	1994-11-23	$7700.00	Window Closed / Lapsed

Oil recovery process using polymer microemulsion complexes

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