Block copolymers for recovering hydrocarbon fluids from a subterranean reservoir
View Patent ↗The present disclosure is directed to compositions and methods that may be used 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, wherein the expandable polymeric monomers have a block copolymer structure comprising at least two different monomers having different chemical structures.
1. A composition comprising:
cross linked expandable polymeric microparticles comprising 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, wherein the expandable polymeric microparticles have a block copolymer structure comprising at least two different monomers having different chemical structures.
2. The composition of claim 1 , wherein the composition is in the form of an emulsion or aqueous suspension.
3. The composition of claim 2 , wherein at least one of the cross linked polymeric microparticles are anionic.
4. The composition of claim 3 , wherein the anionic polymeric microparticles are prepared by free-radical polymerization from about 95 to about 10 mole percent of nonionic monomers and from about 5 to about 90 mole percent of anionic monomers.
5. The composition of claim 4 , wherein the nonionic monomer is acrylamide and the anionic monomer is 2-acrylamido-2-methyl-1-propanesulfonic acid.
6. The composition of claim 5 , wherein the labile cross-linker is polymethyleneglycol diacrylate and the non-labile cross linker is methylene bisacrylamide.
7. The composition of claim 1 , wherein the block copolymer structure is selected from the group consisting of segmented blocks, random blocks, di-blocks, tri-blocks, alternating blocks, periodic blocks, amphiphilic blocks, statistical blocks, star blocks, comb blocks, and combinations thereof.
8. The composition of claim 1 , wherein the block copolymer structure comprises a third monomer having a structure that is different from the structures of the at least two different monomers.
9. The composition of claim 1 , wherein the expandable polymeric microparticles having the block copolymer structure are synthesized using a controlled radical polymerization technique selected from the group consisting of atom transfer radical polymerization, nitroxide-mediated radical polymerization, reversible addition fragmentation chain transfer polymerization, and combinations thereof.
10. The composition of claim 1 , wherein the block copolymer structure comprises a hydrophilic block of poly(N-isopropylacrylamide) and a non-water-soluble block of poly((3-methoxypropyl)acrylamide).
11. The composition of claim 1 , wherein the unexpanded volume average particle size diameter is from about 0.1 to about 3 microns.
12. The composition of claim 1 , wherein the unexpanded volume average particle size diameter is from about 0.1 to about 1 micron.
13. The composition of claim 1 , wherein the labile cross linker is selected from the group consisting of diacrylates and polyfunctional vinyl derivatives of a polyalcohol.
14. The composition of claim 1 , comprising cross linked anionic, amphoteric, ion-pair or betaine-containing polymeric microparticles.
15. A method for improving recovery of hydrocarbon fluids from a subterranean formation comprising injecting into the subterranean formation a composition comprising cross linked expandable polymeric microparticles comprising 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.
16. The method of claim 15 , wherein from about 100 ppm to about 10,000 ppm of the composition, based on polymer actives, is added to the subterranean formation.
17. The method of claim 15 , 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 15 , 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 15 , wherein the composition 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 15 , wherein the subterranean formation is a sandstone or carbonate hydrocarbon reservoir.