Compositions comprising at least two different polymeric microparticles and methods for recovering hydrocarbon fluids from a subterranean reservoir
View Patent ↗The present disclosure is directed to compositions and methods for enhanced oil recovery, for modifying the permeability of subterranean formations and for increasing the mobilization and/or recovery rate of hydrocarbon fluids present in the formations. The compositions may include, for example, expandable cross-linked polymeric microparticles having unexpanded volume average particle size diameters of from about 0.05 to about 5,000 microns and cross linking agent contents of from about 100 to about 200,000 ppm of labile cross linkers and from 0 to about 300 ppm of non-labile cross linkers that may be used in combination with other components such as, for example, a second and different polymeric microparticle, a viscosified aqueous solution, a subterranean reservoir treatment, or combinations thereof.
1. A composition comprising at least two different cross linked expandable polymeric microparticles comprising different chemical structures and unexpanded volume average particle size diameters of about 0.05 to about 5,000 microns and cross linking agent contents of about 100 to about 200,000 ppm of labile cross linkers and from 0 to about 300 ppm of non-labile cross linkers.
2. The composition of claim 1 , wherein at least one of the cross linked polymeric microparticles is selected from the group consisting of cross linked anionic, amphoteric, ion-pair or betaine-containing polymeric microparticles.
3. The composition of claim 2 , wherein the composition is in the form of an emulsion or aqueous suspension.
4. The composition of claim 3 , wherein at least one of the cross linked polymeric microparticles is anionic.
5. The composition of claim 4 , wherein the anionic polymeric microparticle is prepared by free-radical polymerization of from about 95 to about 10 mole percent of nonionic monomers and from about 5 to about 90 mole percent of anionic monomers.
6. The composition of claim 5 , wherein the nonionic monomer is acrylamide.
7. The composition of claim 6 , wherein the anionic monomer is 2-acrylamido-2-methyl-1-propanesulfonic acid.
8. The composition of claim 7 , wherein the labile cross linker is polyethyleneglycol diacrylate.
9. The composition of claim 8 , wherein the non-labile cross linker is methylene bisacrylamide.
10. The composition of claim 1 , wherein at least one of the cross linked polymeric microparticles comprises labile cross linkers selected from the group consisting of diacrylates and polyfunctional vinyl derivatives of a polyalcohol.
11. A method for improving recovery of hydrocarbon fluids from a subterranean formation comprising injecting into the subterranean formation a composition according to claim 1 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.
12. The method of claim 11 , wherein a first cross linked expandable polymeric microparticle is injected before a second cross linked expandable polymeric microparticle.
13. The method of claim 11 , comprising mixing the at least two different cross linked expandable polymeric microparticles prior to the injection.
14. The method of claim 11 , comprising mixing the at least two different cross linked expandable polymeric microparticles during the injection.
15. The method of claim 11 further comprising injecting a viscosified aqueous solution into the subterranean formation.
16. The method of claim 11 further comprising injecting at least one subterranean reservoir treatment into the subterranean formation.
17. The method of claim 11 , wherein the composition is added to injection water as part of a secondary or tertiary process for the recovery of hydrocarbon fluids from the subterranean formation.
18. The method of claim 11 , wherein the composition is injected into the subterranean formation as part of a carbon dioxide and water tertiary recovery project.
19. The method of claim 11 , wherein the composition is injected into the subterranean formation as part of a tertiary oil recovery process, one component of which constitutes water injection.
20. The method of claim 11 , wherein the subterranean formation is a sandstone or carbonate hydrocarbon reservoir.