Claims Analysis
Total Claims: 34
Claim 1
Independent Claim
237 words
A method for recovering oil from a subterranean formation comprising injecting into said formation through one or more injection wells an aqueous composition comprising a thickening amount of a water-soluble polymeric thickener represented by the formula ##STR10## wherein Y is hydrogen, ammonium, an alkali metal or an alkaline earth metal, R 1 and R 2 are independently hydrogen, hydroxyl, halogen, amino, nitro, sulfo, phospho, carboxy, carboxyamido groups or hydrocarbon groups of 1 to about 20 carbon atoms, R 3 is hydrogen or a hydrocarbon group of from 1 to about 12 carbon atoms, R 4 and R 5 are independently hydrogen or alkyl groups of 1 to about 3 carbon atoms; m is a number sufficient to provide the acid or salt portion of said polymer at a level of from zero to about 90% by weight of the total weight of said polymer, n is a number sufficient to provide the amide portion of said polymer at a level of from about 10% to about 99.5% by weight of the total weight of said polymer, p is a number sufficient to provide the maleimide portion of said polymer at a level of at least about 0.2% by weight of the total weight of said polymer, and x is a number sufficient to provide said polymer with a molecular weight of at least about 100,000; and driving oil in said formation toward one or more production wells.
Claim 2
Independent Claim
237 words
A method for recovering oil from a subterranean formation comprising injecting into said formation through one or more injection wells an aqueous composition comprising a thickening amount of a water-soluble polymeric thickener represented by the formula ##STR10## wherein Y is hydrogen, ammonium, an alkali metal or an alkaline earth metal, R 1 and R 2 are independently hydrogen, hydroxyl, halogen, amino, nitro, sulfo, phospho, carboxy, carboxyamido groups or hydrocarbon groups of 1 to about 20 carbon atoms, R 3 is hydrogen or a hydrocarbon group of from 1 to about 12 carbon atoms, R 4 and R 5 are independently hydrogen or alkyl groups of 1 to about 3 carbon atoms; m is a number sufficient to provide the acid or salt portion of said polymer at a level of from zero to about 90% by weight of the total weight of said polymer, n is a number sufficient to provide the amide portion of said polymer at a level of from about 10% to about 99.5% by weight of the total weight of said polymer, p is a number sufficient to provide the maleimide portion of said polymer at a level of at least about 0.2% by weight of the total weight of said polymer, and x is a number sufficient to provide said polymer with a molecular weight of at least about 100,000; and driving oil in said formation toward one or more production wells.
Claim 3
Dependent Claim
78 words
The method of claim 1 wherein said aqueous composition comprises a buffer slug, said method further comprising the steps of: injecting into said formation a surfactant slug to precede said buffer slug, said surfactant slug comprising an aqueous solution containing an effective amount of a surface-active agent to reduce the oil-water interfacial tension and/or alter the wettability characteristics of the rock in said formation, and injecting into said formation an aqueous flooding medium to follow said buffer slug.
Claim 4
Dependent Claim
29 words
The method of claim 1 wherein said polymeric thickener is present in said aqueous composition at a concentration in the range of about 0.05 to about 0.2% by weight.
Claim 5
Dependent Claim
27 words
The method of claim 1 wherein the average temperature of the oil in said formation is in the range of about 15° C. to about 120° C.
Claim 6
Dependent Claim
21 words
The method of claim 1 wherein the water in said aqueous composition has a TDS of up to about 200,000 ppm.
Claim 7
Dependent Claim
23 words
The method of claim 1 wherein said aqueous composition has a divalent or trivalent metal ion concentration of up to about 20,000 ppm.
Claim 8
Dependent Claim
22 words
The method of claim 1 wherein the pH of said aqueous composition is in the range of about 4 to about 12.
Claim 9
Dependent Claim
15 words
The method of claim 1 wherein the water in said aqueous composition is sea water.
Claim 10
Dependent Claim
17 words
The method of claim 1 wherein the pressure within said formation ranges up to about 4000 psi.
Claim 11
Dependent Claim
26 words
The method of claim 2 wherein the amount of said surfactant slug injected into said formation is equal to about 0.2 to about 3 pore volumes.
Claim 12
Dependent Claim
26 words
The method of claim 2 wherein the amount of said buffer slug injected into said formation is equal to about 0.6 to about 3 pore volumes.
Claim 13
Dependent Claim
47 words
The method of claim 2 wherein said surfactant slug contains a thickening amount of the polymeric thickener in said buffer slug, the amount of said thickener in said buffer slug exceeding the amount of said thickener in said surfactant slug by at least about 0.02% by weight.
Claim 14
Dependent Claim
11 words
The method of claim 1 wherein Y is an alkali metal.
Claim 15
Dependent Claim
9 words
The method of claim 1 wherein Y is sodium.
Claim 16
Dependent Claim
23 words
The method of claim 1 wherein R 1 , R 2 , R 3 , R 4 and R 5 are each hydrogen.
Claim 17
Dependent Claim
36 words
The method of claim 1 wherein R 1 , R 2 , R 4 and R 5 are each hydrogen and R 3 is an alkyl or aryl group of up to about 10 carbon atoms.
Claim 18
Dependent Claim
42 words
The method of claim 1 wherein m is a number sufficient to provide the acid or salt portion of said polymeric thickener at a level of from about 10% to about 50% by weight of the total weight of said polymeric thickener.
Claim 19
Dependent Claim
40 words
The method of claim 1 wherein n is a number sufficient to provide the amide portion of said polymeric thickener at a level of from about 50% to about 90% by weight of the total weight of said polymeric thickener.
Claim 20
Dependent Claim
40 words
The method of claim 1 wherein p is a number sufficient to provide the maleimide portion of said polymeric thickener at a level of from about 0.2% to about 20% by weight of the total weight of said polymeric thickener.
Claim 21
Dependent Claim
38 words
The method of claim 1 wherein m is a number sufficient to provide the acid or salt portion of said polymeric thickener at a level of about 30% by weight of the total weight of said polymeric thickener.
Claim 22
Dependent Claim
36 words
The method of claim 1 wherein n is a number sufficient to provide the amide portion of said polymeric thickener at a level of about 70% by weight of the total weight of said polymeric thickener.
Claim 23
Dependent Claim
40 words
The method of claim 1 wherein p is a number sufficient to provide the maleimide portion of said polymeric thickener at a level of from about 0.5% to about 10% by weight of the total weight of said polymeric thickener.
Claim 24
Dependent Claim
40 words
The method of claim 1 wherein p is a number sufficient to provide the maleimide portion of said polymeric thickener at a level of from about 0.5% to about 2% by weight of the total weight of said polymeric thickener.
Claim 25
Dependent Claim
40 words
The method of claim 1 wherein p is a number sufficient to provide the maleimide portion of said polymeric thickener at a level of from about 0.5% to about 1% by weight of the total weight of said polymeric thickener.
Claim 26
Dependent Claim
24 words
The method of claim 1 wherein the portion of said polymeric thickener represented by the formula ##STR11## is derived from maleimide or 1,1'-(methylenedi-4,1-phenylene)bis maleimide.
Claim 27
Dependent Claim
24 words
The method of claim 1 wherein x is a number sufficient to provide said polymer with a molecular weight of at least about 1,000,000.
Claim 28
Independent Claim
98 words
A method for recovering oil from a subterranean formation comprising injecting into said formation a thickening amount of a water-soluble polymeric thickener, said polymeric thickener comprising a copolymer derived from monomers consisting of acrylamide and maleimide, said copolymer having a molecular weight of at least about 100,000, a maleimide content of from about 0.2% to about 20% by weight of the total weight of said copolymer, and an acrylamide content of from about 80% to about 99.8% by weight of the total weight of said copolymer, and driving oil in said formation toward one or more production wells.
Claim 29
Independent Claim
98 words
A method for recovering oil from a subterranean formation comprising injecting into said formation a thickening amount of a water-soluble polymeric thickener, said polymeric thickener comprising a copolymer derived from monomers consisting of acrylamide and maleimide, said copolymer having a molecular weight of at least about 100,000, a maleimide content of from about 0.2% to about 20% by weight of the total weight of said copolymer, and an acrylamide content of from about 80% to about 99.8% by weight of the total weight of said copolymer, and driving oil in said formation toward one or more production wells.
Claim 30
Dependent Claim
17 words
The method of claim 27 wherein said copolymer has a molecular weight of at least about 1,000,000.
Claim 31
Independent Claim
122 words
A method for recovering oil from a subterranean formation comprising injecting into said formation an aqueous composition comprising a thickening amount of a water-soluble polymeric thickener, said polymeric thickener comprising a terpolymer derived from acrylamide, an alkali metal acrylate and a maleimide, said terpolymer having molecular weight of at least about 100,000, a maleimide content of from about 0.2% to about 20% by weight of the total weight of said terpolymer, an acrylamide content of from about 10% to about 99.8% by weight of the total weight of said terpolymer, and an alkali metal acrylate content of up to about 90% by weight of the total weight of said terpolymer, and driving oil in said formation toward one or more production wells.
Claim 32
Independent Claim
122 words
A method for recovering oil from a subterranean formation comprising injecting into said formation an aqueous composition comprising a thickening amount of a water-soluble polymeric thickener, said polymeric thickener comprising a terpolymer derived from acrylamide, an alkali metal acrylate and a maleimide, said terpolymer having molecular weight of at least about 100,000, a maleimide content of from about 0.2% to about 20% by weight of the total weight of said terpolymer, an acrylamide content of from about 10% to about 99.8% by weight of the total weight of said terpolymer, and an alkali metal acrylate content of up to about 90% by weight of the total weight of said terpolymer, and driving oil in said formation toward one or more production wells.
Claim 33
Dependent Claim
14 words
The method of claim 29 wherein said alkali metal acrylate is a sodium acrylate.
Claim 34
Dependent Claim
17 words
The method of claim 29 wherein said terpolymer has a molecular weight of at least about 1,000,000.