Method of recovering hydrocarbon fluids from a subterranean reservoir
First Claim
1. A method of modifying the permeability to water of a subterranean formation comprising injecting into the subterranean formation a composition comprising highly cross linked expandable polymeric microparticles having an unexpanded volume average particle size diameter of from about 0.05 to about 10 microns and a cross linking agent content of about 1,000 to less than about 9,000 ppm of labile cross linkers and from 0 to about 300 ppm of non-labile cross linkers, wherein the microparticles have a smaller diameter than the pores of the subterranean formation and wherein the labile cross linkers break under the conditions of temperature and pH in the subterranean formation to form expanded microparticles.
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Abstract
This invention is directed to a composition comprising expandable cross linked polymeric microparticles having an unexpanded volume average particle size diameter of from about 0.05 to about 10 microns and a cross linking agent content of about 1,000 to less than about 9,000 ppm of labile cross linkers and from 0 to about 300 ppm of non-labile cross linkers and to the use of the composition for modifying the permeability of subterranean formations and increasing the mobilization and/or recovery rate of hydrocarbon fluids present in the formations.
104 Citations
31 Claims
- 1. A method of modifying the permeability to water of a subterranean formation comprising injecting into the subterranean formation a composition comprising highly cross linked expandable polymeric microparticles having an unexpanded volume average particle size diameter of from about 0.05 to about 10 microns and a cross linking agent content of about 1,000 to less than about 9,000 ppm of labile cross linkers and from 0 to about 300 ppm of non-labile cross linkers, wherein the microparticles have a smaller diameter than the pores of the subterranean formation and wherein the labile cross linkers break under the conditions of temperature and pH in the subterranean formation to form expanded microparticles.
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12. The method of claim 99 wherein the anionic monomer is 2-acrylamido-2-methyl-1-propanesulfonic acid.
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24. A method of increasing the mobilization or recovery rate of hydrocarbon fluids in a subterranean formation comprising injecting into the subterranean formation a composition comprising highly cross linked expandable polymeric microparticles having an unexpanded volume average particle size diameter of from about 0.05 to about 10 microns and a cross linking agent content of about 1,000 to less than about 9,000 ppm of labile cross linkers and from 0 to about 300 ppm of non-labile cross linkers, wherein the microparticles have a smaller diameter than the pores of the subterranean formation and wherein the labile cross linkers break under the conditions of temperature and pH in the subterranean formation to decrease the mobility of the composition.
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31. A method of preparing highly cross linked expandable polymeric microparticles having an unexpanded volume average particle size diameter of from about 0.05 to about 10 microns comprising polymerizing one or more allylic, vinylic or acrylic monomers under free-radical forming conditions in the presence of about 1,000 to less than about 9,000 ppm of labile cross linkers and 0 to about 300 ppm of non-labile cross linkers.
Specification