Foam-forming surfactant compositions
This invention relates to foam-forming surfactant compositions having at least two surfactants whereof at least one is a sulfosuccinamate, and at least one is a sulfosuccinate, and optionally including, a solvent. Methods of recovering oil or gas by generating a foam, feeding the foam into a subterranean oil- or gas-bearing geological formation, and collecting mineral oil or natural gas driven by the foam in a production well, wherein the foam is generated by intimate mixing of one or more foam-forming surfactant compositions described herein with a gas in a foam generator, or by introduction of at least one of water and gases, together or intermittently or in alternating sequence, slugs of a gas which may be in a supercritical or non-supercritical state, and of water, wherein the foam-forming surfactant composition(s) can be admixed to the water or to the gas if the gas is in a supercritical state or be introduced separately as solution into the geological formation, are also provided.
1. A foam-forming surfactant composition comprising at least one sulfosuccinamate surfactant compound of formula:
R—NX—CO—CHY 1 —CHY 2 —CO—O − M 4+ , (Formula I),
where
Y 1 is H and Y 2 is (SO 3 − M 3+ ), or Y 1 is (SO 3 − M 3+ ) and Y 2 is H,
R is a linear or branched or cyclic aliphatic radical having from four to twenty-four carbon atoms, and
X is an alkylcarboxylate group —(CR a R b )—COO − M 2+ where R a and R b may both be H, or one of R a or R b is H and the other is —CH 2 —COO − M 1+ , where M 1+ and M 2+ and M 3+ and M 4+ may be the same or different, and each is independently selected from the group consisting of the cations of the chemical elements of groups 1 and 2 of the Periodic Table of the Elements, consisting of the alkali metals, and the earth alkali metals, and from ammonium NH 4 + ; and
at least one monoester sulfosuccinate surfactant compound of formula
R 1 —O—CO—CHY 3 —CHY 4 —CO—O—R 2 , (Formula III),
where
Y 3 is H and Y 4 is (SO 3 − M + ), or Y 3 is (SO 3 − M + ) and Y 4 is H;
one of R 1 and R 2 may be selected from the group consisting of linear or branched or cyclic aliphatic radicals having from four to twenty-four carbon atoms, and
the other of R 1 and R 2 is a hydrogen atom or an alkali metal selected from the group consisting of the cations of the chemical elements of groups 1 and 2 of the Periodic Table of the Elements, consisting of the alkali metals, and the earth alkali metals, and from ammonium NH 4 + , and
M + is selected from the group consisting of the cations of the chemical elements of groups 1 and 2 of the Periodic Table of the Elements, consisting of the alkali metals, and the earth alkali metals, and from ammonium NH 4 + .
2. A foam-forming surfactant composition according to claim 1 further comprising a solvent selected from the group consisting of water, aqueous salt solutions, liquefied gases, supercritical gases, and mixtures thereof.
3. The foam-forming surfactant composition of claim 1 , wherein the mass fraction w(SF) of the surfactants, calculated as the ratio of the sum of their masses m(SF) to the mass m(FC) of the foam-forming surfactant composition, is from 0.5 g/kg to 100 g/kg.
4. The foam-forming surfactant composition of claim 1 , further comprising a diester sulfosuccinate surfactant represented by the formula
R 1 —O—CO—CHY 3 —CHY 4 —CO—O—R 2 , (Formula III)
where
Y 3 is H and Y 4 is (SO 3 − M + ), or Y 3 is (SO 3 − M + ) and Y 4 is H;
both R 1 and R 2 may be the same or different, and each is independently selected from the group consisting of linear or branched or cyclic aliphatic radicals having from four to twenty-four carbon atoms, and
M + is selected from the group consisting of the cations of the chemical elements of groups 1 and 2 of the Periodic Table of the Elements, consisting of the alkali metals, and the earth alkali metals, and from ammonium NH 4 + .
5. The foam-forming surfactant composition of claim 4 , wherein
each of R 1 and R 2 is selected from a branched saturated alkyl group having from four to eight carbon atoms.
6. The foam-forming surfactant composition of claim 1 , wherein
X is an alkyl-dicarboxylate group —CH[—CH 2 —COO − M 1+] ]—COO − M 2+ .
7. The foam-forming surfactant composition of claim 1 , wherein the monoester sulfosuccinate is selected from the group consisting of monoester sulfosuccinates having polyoxyethylene moieties in their molecules.
8. The foam-forming surfactant composition of claim 4 , wherein the ratio of the mass m(SSA) of sulfosuccinamates (“SSA”) to the sum of the mass m(MSS) of monoester sulfosuccinates (“MSS”) and the mass m(DSS) of diester sulfosuccinates (“DSS”) is 1:99≤m(SSA)/[m(MSS)+m(DSS)]≤99:1.
9. The foam-forming surfactant composition of claim 1 , wherein the cations of the sulfosuccinamate surfactant are independently selected from the group consisting of Li + , Na + , and K + .
10. The foam-forming surfactant composition of claim 9 wherein in the sulfosuccinamate surfactant, all cations are sodium cations, Na + .
11. The foam-forming surfactant composition of any one of claims 1 - 3 , 4 , 6 , and 7 , wherein when R of Formula (I), R of Formula (II), R 1 of Formula (III), or R 2 of Formula (III) is selected from the group consisting of linear or branched or cyclic aliphatic radicals having from four to twenty-four carbon atoms, said radical includes one or more carbon-carbon double bond or a mixture of two or more of said radicals.
12. The foam-forming surfactant composition of claim 11 , wherein the sulfosuccinamate surfactant is a mixture of the sodium salts of sulfosuccinamate surfactants that have mixtures of saturated octadecyl and mono-unsaturated octadecenyl radicals in their molecules as alkyl groups.
13. A method of recovering oil or gas from a subterranean oil- or gas-bearing geological formation comprising the following steps:
generating a foam using a foam-forming surfactant composition of claim 1 ,
feeding the foam into a subterranean oil- or gas-bearing geological formation; and
collecting mineral oil or natural gas driven by the foam in a production well, wherein the foam is generated by
intimate mixing of the foam-forming surfactant composition of claim 1 with a gas in a foam generator,
or by
introducing at least one of water and gases, together or intermittently or in alternating sequence, or slugs of a gas in a supercritical or non-supercritical state, and of water, wherein the foam-forming surfactant composition of claim 1 is admixed to the water or to the gas if the gas is in a supercritical state, or is introduced separately as solution into a subterranean oil- or gas-bearing geological formation.
14. The method of claim 13 , wherein the feeding and collecting steps are performed at a temperature of from 10 ° C. to 95 ° C., and wherein the foam-forming surfactant composition further comprises a diester sulfosuccinate, wherein the ratio of the mass m(SSA) of sulfosuccinamates to the sum m(MSS)+m(DSS) of the mass m(MSS) of monoester sulfosuccinates and the mass m(DSS) of diester sulfosuccinates is 20:80<m(SSA)/[m(MSS)+m(DSS)]<95:5.
15. The method of claim 13 , wherein the mass fraction w(SF) of the surfactants present in the foam-forming surfactant composition of claim 1 , calculated as the ratio of the sum of their masses m(SF) to the mass m(FC) of the aqueous foam-forming surfactant composition, is from 0.5 g/kg to 100 g/kg.
16. The method of claim 13 , wherein the sulfosuccinamate surfactant of the foam-forming surfactant composition of claim 1 is a mixture of the sodium salts of sulfosuccinamate surfactants that comprise mixtures of saturated octadecyl and mono-unsaturated octadecenyl radicals in their molecules as alkyl groups.
17. The method of claim 13 , wherein the subterranean oil- or gas-bearing geological formation has a temperature of at least 25 ° C.
18. The method of claim 17 , wherein the foam-forming surfactant composition and/or the water present in the subterranean oil- or gas-bearing geological formation comprises a mass fraction of at least 0.2% of dissolved inorganic salts.