Process for improving the gas sweeping of an oil formation, using foams mainly containing surfactants with perfluoric groups

Claim 2

A process for enhanced recovery of hydrocarbons present in a subsurface reservoir comprising injecting through at least one injection well a plug of a solution of at least one surfactant and a gas, so as to form a foam, and wherein at least a part of said reservoir is swept by said foam and hydrocarbons are recovered from at least one producing well, wherein the surfactant has the formula (I) R.sub.F --Y--X (I) wherein R F is a perfluoric carbon radical, Y is a divalent hydrocarbon radical or a divalent radical containing at least one oxygen, sulfur or nitrogen atom, and X is a hydrophilic group.

Claim 3

A process according to claim 1, wherein the perfluoric radical R F is a linear or branched perfluoroalkyl radical containing 1 to 20 carbon atoms.

Claim 4

A process according to claim 2, wherein R F contains 4-14 carbon atoms.

Claim 5

A process according to claim 1, wherein the surfactant has the formula (II): ##STR11## wherein RF and Y are defined above and the remainder of the molecule corresponds to group X, n is an integer from 1 to 12, each of symbols R 1 , R 2 and R 3 , (a) being identical or different, represents a hydrogen atom, an alkyl radical of 1-8 C carbon atoms, a cycloalkyl radical of 5-10 carbon atoms, an alkenyl radical of 2-8 carbon atoms, a cycloalkenyl radical of 5-10 carbon atoms, a hydroxyalkyl radical containing 2 or 3 carbon atoms or an aryl radical, (b) two of R, R 2 and R 3 form together a divalent radical linked with the nitrogen atom by two single bonds, or (c) R 1 , R 2 and R 3 form, together with the nitrogen atom, an aromatic tertiary amine radical containing 5 to 18 carbon atoms; and A - is an anion selected from the group consisting of a halide, a sulfate, an alkylsulfate, a phosphate, a sulfonate, an alkylsulfonate, an arylsulfonate, an alkanoate and a hydroxyl ion.

Claim 6

A process according to claim 4, wherein n is 2.

Claim 7

A process according to claim 1, wherein said surfactant has the formula (III): ##STR12## wherein: ##STR13## corresponds to radical Y of formula (I) and wherein: ##STR14## R F is a perfluoric group defined in formula (I), m is zero or an integer from 1 to 12, G is a divalent CO or SO 2 radical, R is a hydrogen atom or an alkyl group of 1-4 carbon atoms, p is zero or an integer from 1 to 10, R' 1 and R' 2 , are identical different, and are alkyl groups having 1 to 4 carbon atoms, q is an integer from 1 to 20, and Z is a sulfonate or carboxylate group.

Claim 8

A process according to claim 6, wherein m is 2.

Claim 9

A process according to claim 1, wherein said surfactant has the formula (IV): ##STR15## wherein m is zero or 1 to 12, G is a divalent CO or SO 2 radical, R is a hydrogen atom or an alkyl group of 1-4 carbon atoms, p is zero or 1 to 10, each of symbols R 1 , R 2 and R 3 , identical or different, represents a hydrogen atom, or an alkyl radical of 1-8 carbon atoms, a cycloalkyl radical of 5-10 carbon atoms, an alkenyl radical of 2-8 carbon atoms, a cycloalkenyl radical of 5-10 carbon atoms, a hydroxyalkyl radical containing 2 or 3 carbon atoms, or an aryl radical, (b) two of said symbols form together a divalent radical linked with the nitrogen atom by two single bonds, or (c) R 1 , R 2 and R 3 form, together with the nitrogen atom, an aromatic tertiary amine radical containing 5 to 18 carbon atoms; and A - is an anion selected from the group consisting of a halide, a sulfate, an alkylsulfate, a phosphate, a sulfonate, an alkylsulfonate, an arylsulfonate, an alkanoate and a hydroxyl ion.

Claim 10

A process according to claim 1, wherein said surfactant has the formula (V): ##STR16## wherein m is zero or 1 to 12, G is a divalent CO or SO 2 radical, R is a hydrogen atom or an alkyl group of 1-4 carbon atoms, p is zero or 1 to 10, and R 4 and R 5 are alkyl radicals of 1-6 carbon atoms.

Claim 11

A process according to claim 1, wherein said surfactant has the formula (VI): ##STR17## wherein: X is a iodine, chlorine or bromine atom, m' is zero, 1 or 2, n' is a number from 5 to 1000, R 6 is a hydrogen atom or a methyl radical, R 7 is a --COOH or CONR 8 R 9 group, each of symbols R 8 and R 9 , are identical or different and are a hydrogen atom, an alkyl radical or a hydroxyalkyl radical.

Claim 12

A process according to claim 1, characterized in that the surfactant has the formula (VII): ##STR18##

Claim 13

A process according to claim 1, wherein the surfactant has the formula (VIII): ##STR19## wherein R F is a perfluoric radical having 6, 8, 10 or 12 perfluoric carbon atoms.

Claim 14

A process according to claim 12, wherein the surfactant consists essentially of a mixture of surfactants of formula VIII.

Claim 15

A process according to claim 1, wherein, for a foam quality varying from 70% to 99.9% and preferably from 85 to 99%, the surfactant with perfluoric groups is present in an aqueous solution in a proportion varying from 0.05 to 10%, preferably from 0.5 to 2% by weight, and in that the gas used for the foam preparation is steam, air, nitrogen, utility gases, carbon dioxide, methane, natural gas or a mixture thereof.

Claim 16

A process according to claim 1, wherein the surfactant has the formula: ##STR20## wherein R F' is a mixture of perfluoric radicals comprising C 6 F 13 , C 8 F 17 and C 10 F 21 .

Claim 17

A process according to claim 1, wherein the gas used for foam preparation is a mixture of steam and at least one of air, nitrogen, utility gases, carbon dioxide, methane or natural gas.

Claim 18

A process according to claim 1, wherein Y is a divalent radical containing carbon and at least one oxygen, nitrogen or sulfur atom.

Claim 19

A process for enhanced recovery of hydrocarbons present in a subsurface reservoir comprising injecting through at least one injection well of a plug of a solution of at least one surfactant and a gas, so as to form a foam, and wherein at least a part of said reservoir is swept by said foam and hydrocarbons are recovered from at least one producing well, wherein the surfactant has the formula ##STR21## wherein R F is a perfluoric carbon radical, Y is a single bond or a divalent hydrocarbon radical or a divalent radical containing at least one oxygen, sulfur or nitrogen atom, and R 1 , R 2 and R 3 , (a) being identical or different, represents a hydrogen atom or an alkyl radical of 1-8 C carbon atoms, a cycloalkyl radical of 5-10 carbon atoms, an alkenyl radical of 2-8 carbon atoms, a cycloalkenyl radical of 5-10 carbon atoms, a hydroxyalkyl radical containing 2 or 3 carbon atoms or an aryl radical, (b) two of said symbols R, R 2 and R 3 optionally forming together a divalent radical linked with the nitrogen atom by two single bonds, or (c) R 1 , R 2 and R 3 form, together with the nitrogen atom, the remainder of an aromatic tertiary amine derived from pyridine and radical containing 5 to 18 carbon atoms; and A - is an anion selected from the group consisting of a halide, a sulfate, an alkylsulfate, a phosphate, a sulfonate, an alkylsulfonate, an arylsulfonate, an alkanoate and a hydroxyl ions.

Claim 20

A process for enhanced recovery of hydrocarbons present in a subsurface reservoir comprising injecting through at least one injection well of a plug of a solution of at least one surfactant and a gas, so as to form a foam, and wherein at least a part of said reservoir is swept by said foam and hydrocarbons are recovered from at least one producing well, wherein the surfactant has the formula ##STR21## wherein R F is a perfluoric carbon radical, Y is a single bond or a divalent hydrocarbon radical or a divalent radical containing at least one oxygen, sulfur or nitrogen atom, and R 1 , R 2 and R 3 , (a) being identical or different, represents a hydrogen atom or an alkyl radical of 1-8 C carbon atoms, a cycloalkyl radical of 5-10 carbon atoms, an alkenyl radical of 2-8 carbon atoms, a cycloalkenyl radical of 5-10 carbon atoms, a hydroxyalkyl radical containing 2 or 3 carbon atoms or an aryl radical, (b) two of said symbols R, R 2 and R 3 optionally forming together a divalent radical linked with the nitrogen atom by two single bonds, or (c) R 1 , R 2 and R 3 form, together with the nitrogen atom, the remainder of an aromatic tertiary amine derived from pyridine and radical containing 5 to 18 carbon atoms; and A - is an anion selected from the group consisting of a halide, a sulfate, an alkylsulfate, a phosphate, a sulfonate, an alkylsulfonate, an arylsulfonate, an alkanoate and a hydroxyl ions.