Method for remediation of damage in regions of formations near injection wells
Aspects of the invention relate to compositions and methods that are used for the remediation of near-wellbore damage in regions of formations near injection wells in communication with subterranean reservoirs. The damage is caused by previous injection of a polymer emulsion into the injection well. A specific aspect is a method of injecting into the subterranean reservoir a composition containing an olefin sulfonate, a sulfosuccinate, and a chemical selected from an alcohol alkoxylated sulfate, an alcohol alkoxylated carboxylate, or a combination thereof. The polymer emulsion is thereby dissolved, cleaned and/or flushed away from the region near the injection well.
1. A method for remediation of existing damage in a region of a formation near an injection well in communication with a subterranean reservoir, the method comprising: injecting into the subterranean reservoir a composition comprising an aqueous solution of an internal olefin sulfonate, wherein the injection well is not intended for receiving hydrocarbons and wherein the existing damage is caused by previous injection of a polymer emulsion into the injection well, wherein the polymer emulsion is thereby dissolved, cleaned and/or flushed away from the region near the injection well.
2. The method of claim 1 , wherein the internal olefin sulfonate comprises C 15-18 internal olefin sulfonates, C 20-28 internal olefin sulfonates, or a combination thereof.
3. The method of claim 2 , wherein the C 20-28 internal olefin sulfonate is an isomerized C 20-28 alpha olefin sulfonate.
4. The method of claim 3 , wherein the isomerized C 20-28 alpha olefin sulfonate comprises about 20-98 percent branching.
5. The method of claim 1 , wherein the composition further comprises an alkoxylated alcohol.
6. The method of claim 5 , wherein the alkoxylated alcohol comprises an alcohol alkoxylated sulfate.
7. The method of claim 6 , wherein the alcohol alkoxylated sulfate is tridecyl-8(PO)—SO 4 − , tridecyl-4(PO)—SO 4 − , tridecyl-12(PO)—SO 4 − , or a salt thereof.
8. The method of claim 5 , wherein the alkoxylated alcohol comprises an alcohol alkoxylated carboxylate.
9. The method of claim 1 , wherein the composition further comprises a sulfosuccinate.
10. The method of claim 9 , wherein the sulfosuccinate comprises sodium dihexyl sulfosuccinate or dianyl sulfosuccinate.
11. The method of claim 10 , wherein the dihexyl sulfosuccinate is partially derived from a 4-methyl-2-pentanol feedstock.
12. The method of claim 1 , wherein the composition further comprises at least one additive selected from alkali, chelators, co-solvents, polymers, and electrolytes.
13. The method of claim 12 , wherein the at least one additive is a co-solvent selected from ethylene glycol butyl ether, isopropyl alcohol, ethanol, n-propyl alcohol, n-butyl alcohol, sec-butyl alcohol, n-amyl alcohol, sec-amyl alcohol, n-hexyl alcohol, sec-hexyl alcohol, polyalkylene alcohol ethers, polyalkylene glycols, poly(oxyalkylene)glycols, and (oxyalkylene)glycols ethers.
14. The method of claim 1 , wherein the aqueous solution of the internal olefin sulfonate comprises C 20-28 internal olefin sulfonate and the composition further comprises two or more chemicals selected from the group consisting of C 15-18 internal olefin sulfonates, an alcohol alkoxylated sulfate, an alcohol alkoxylated carboxylate, and a sulfosuccinate and wherein each chemical comprises between 0.5% by weight to 15% by weight of the composition.
15. The method of claim 14 , wherein each chemical comprises between 0.5% and 3% by weight of the composition.
16. The method of claim 1 , wherein the aqueous solution of the internal olefin sulfonate comprises C 15-18 internal olefin sulfonates and C 20-28 internal olefin sulfonates; and the composition further comprises an alkali and an alcohol alkoxylated carboxylate.
17. The method of claim 1 , wherein the aqueous solution of the internal olefin sulfonate comprises C 20-28 internal olefin sulfonates; and the composition further comprises an alcohol alkoxylated sulfate and a sulfosuccinate.
18. The method of claim 1 , wherein the temperature of the subterranean reservoir is below 55° C.
19. The method of claim 1 , wherein the existing damage comprises plugging in the formation near the wellbore.
20. The method of claim 1 , wherein relative permeability in the region near the injection well is increased due to the polymer emulsion being dissolved, cleaned and/or flushed away from the region near the injection well.
21. The method of claim 20 , wherein the relative permeability in the region near the injection well is increased by at least 0.25.
22. The method of claim 20 , wherein the relative permeability in the region near the injection well is increased by at least 0.5.
23. The method of claim 1 , further comprising subsequent injection of polymer emulsion into the injection well wherein the relative permeability in the region near the injection well decreases at a lower rate compared to rate of relative permeability change without the injection of the composition.