Foam-forming composition for steam assisted oil recovery
The present invention includes a foam-forming composition for use in enhanced heavy oil recovery, and a method of using said foam-forming composition for recovering heavy oil and/or bitumen. The foam-forming composition of the present invention comprises a mixture of (di)alkyl diphenyloxide (di)sulfonate compounds and the process of heavy oil recovery is performed at elevated temperatures using steam.
1. A method for recovering oil from a reservoir formation that is penetrated by at least one injection well and one production well, comprising
(a) selecting a foam-forming composition comprising
(i) an aqueous mixture comprising two or more (di)alkyl diphenyloxide (di)sulfonate compounds having the formulas:
where R is a C 3 to C 24 alkyl group
and
X is H, an alkali metal, alkaline earth metal, a divalent metal, or ammonium, wherein the aqueous mixture of (di)alkyl diphenyloxide (di)sulfonate compounds has a pH equal to or greater than 7 and contains I, the dialkyl diphenyloxide disulfonate (DADS), in an amount equal to or greater than 50 weight percent with the remaining 50 weight percent or less comprising one or more of II, the monoalkyl diphenyloxide disulfonate (MADS), III, the dialkyl diphenyloxide monosulfonate (DAMS), and/or IV, the monoalkyl diphenyloxide monosulfonate (MAMS), weight percent based on the combined weight of the mixture of (di) alkyl diphenyloxide (di)sulfonate compounds;
(b) injecting the foam-forming composition with steam into the injection well and forming a stable foam in the reservoir;
(c) lowering a viscosity of oil in the reservoir formation;
and
(d) producing oil having the lowered viscosity from the reservoir formation.
2. The method of claim 1 wherein R is a C 16 alkyl group and X is sodium, calcium, or magnesium.
3. The method of claim 1 , where the a foam-forming composition further comprises one or more additive selected from a corrosion inhibitor, a scale inhibitor, an antioxidant, a nonionic surfactant, another anionic surfactant, different from (i), a cationic surfactant, a foaming agent, and mixtures thereof.
4. The method of claim 1 where in the injection well and the production well are the same well.
5. The method of claim 4 is cyclic steam stimulation (CSS).
6. The method of claim 1 where in the injection well and the production well are not the same well.
7. The method of claim 6 is steam assisted gravity drainage (SAGD).
8. The method of claim 1 wherein the aqueous mixture of (di)alkyl diphenyloxide (di)sulfonate compounds has a pH equal to or greater than 7 and comprises at least 1 wt % monoalkyl diphenyloxide monosulfonate (MAMS), 10 wt % monoalkyl diphenyloxide disulfonate (MADS), 7 wt % dialkyl diphenyloxide monosulfonate (DAMS), 75 wt % dialkyl diphenyloxide disulfonate (DADS).