Crosslinking of swellable polymer with pei

Abstract

The invention is directed to stable and labile crosslinked water swellable polymeric microparticles that can be further gelled, methods for making same, and their various uses in the hygiene and medical arts, gel electrophoresis, packaging, agriculture, the cable industry, information technology, in the food industry, papermaking, use as flocculation aids, and the like. More particularly, the invention relates to a composition comprising expandable polymeric microparticles having labile crosslinkers and stable crosslinkers, said microparticle mixed with a fluid and an unreacted tertiary crosslinker comprising PEI or other polyamine based tertiary crosslinker that is capable of further crosslinking the microparticle on degradation of the labile crosslinker and swelling of the particle, so as to form a stable gel. A particularly important use is as an injection fluid in petroleum production, where the expandable polymeric microparticles are injected into a well and when the heat and/or pH of the well cause degradation of the labile crosslinker and when the microparticle expands, the tertiary crosslinker crosslinks the polymer to form a stable gel, thus diverting water to lower permeability regions and improving oil recovery.

What is claimed is: 
     
         1 . A composition comprising expandable acrylamide-based polymeric microparticles having labile crosslinkers and stable crosslinkers, said microparticles combined with a fluid and an unreacted tertiary crosslinker comprising polyethyleneimine (“PEI”) that is capable of further crosslinking the microparticles upon degradation of the labile crosslinker so as to form a stable gel. 
     
     
         2 . The composition of  claim 1 , wherein said microparticles comprise polyacrylamide. 
     
     
         3 . The composition of  claim 1 , wherein the microparticles comprise a copolymer of an acrylamide and an acid or salt form of 2-acrylamido-2-methylpropane sulfonate. 
     
     
         4 . The composition of  claim 1 , wherein the stable crosslinker is methylene bisacrylamide and the labile crosslinker is a polyethylene glycol diacrylate. 
     
     
         5 . The composition of  claim 1 , wherein said microparticles comprise a copolymer of acrylamide and 2-acrylamido-2-methylpropane sulfonate, the stable crosslinker comprises methylene bisacrylamide, and the labile crosslinker comprises a polyethylene glycol diacrylate. 
     
     
         6 . The composition of  claim 1 , wherein the expandable polymeric microparticles comprises a copolymer of acrylamide and 2-acrylamido-2-methylpropane sulfonate, the stable crosslinker comprises 1 to about 300 ppm methylene bisacrylamide, the labile crosslinker comprises 9,000 to about 200,000 ppm polyethylene glycol diacrylate, and the tertiary crosslinker comprises 200-2000 ppm PEI and a fluid containing water. 
     
     
         7 . A composition comprising highly cross linked expandable hydrophilic polymeric microparticles having an unexpanded volume average particle size diameter of about 0.05-10 microns and a cross linking agent content of about 10,000-250,000 ppm of labile crosslinkers and about 1-500 ppm of stable cross linkers, combined with about 200-2000 ppm of unreacted PEI and a fluid comprising water. 
     
     
         8 . The composition of  claim 7 , wherein said microparticles comprise polyacrylamide or partially hydrolyzed polyacrylamide. 
     
     
         9 . The composition of  claim 7 , wherein said microparticles comprise a copolymer of acrylamide and 2-acrylamido-2-methylpropane sulfonate. 
     
     
         10 . The composition of  claim 7 , wherein the stable crosslinker is methylene bisacrylamide and the labile crosslinker is a diacrylate. 
     
     
         11 . The composition of  claim 8 , wherein said microparticles comprise a copolymer of acrylamide and 2-acrylamido-2-methylpropane sulfonate, the stable crosslinker comprises methylene bisacrylamide, and the labile crosslinker comprises a polyethylene glycol diacrylate. 
     
     
         12 . A composition comprising:
 a) a highly crosslinked expandable hydrophilic polymeric microparticle;   b) said microparticle having an unexpanded average particle size diameter of 0.05-10 microns;   c) said hydrophilic polymer having amine/amide groups;   d) said hydrophilic polymer being internally crosslinked with 10,000-250,000 ppm of labile crosslinkers and 1-500 ppm of stable crosslinkers; and   e) said microparticle combined with 200-2000 ppm of unreacted tertiary crosslinker that can further crosslink said hydrophilic polymer, wherein said tertiary crosslinker is selected from the group consisting of polyalkyleneimine, a polyethyleneimine, a polyalkylenepolyamine, PEI, simple polyamines, methylene diamine, ethylene diamine, hexamethylene diamine, and hexamethylene triamine.   
     
     
         13 . The composition of  claim 12 , said hydrophilic polymer comprising polymers and copolymers of acrylamide and derivatives thereof. 
     
     
         14 . The composition of  claim 12 , wherein the stable crosslinker is methylene bisacrylamide and the labile crosslinker is a diacrylate. 
     
     
         15 . The composition of  claim 13 , wherein the stable crosslinker is methylene bisacrylamide and the labile crosslinker is a diacrylate. 
     
     
         16 . The composition of  claim 12 , further comprising a tertiary crosslinker retarder. 
     
     
         17 . The composition of  claim 12 , further comprising a carbonate retarder. 
     
     
         18 . A method of increasing the recovery of hydrocarbon fluids in a subterranean formation, comprising injecting into the subterranean formation a mixture comprising water and the composition of  claim 1 , aging said mixture until it gels, and then producing hydrocarbon from said subterranean formation. 
     
     
         19 . A method of increasing the recovery of hydrocarbon fluids in a subterranean formation, comprising:
 a) injecting into the subterranean formation a mixture comprising water and expandable acrylamide-based polymeric microparticles having labile crosslinkers and stable crosslinkers, and   b) injecting an unreacted tertiary crosslinker into the subterranean formation, wherein said tertiary crosslinker is selected from the group consisting of polyalkyleneimine, a polyethyleneimine, a polyalkylenepolyamine, polyethyleneimine, simple polyamines, methylene diamine, ethylene diamine, hexamethylene diamine, and hexamethylene triamine.   
     
     
         20 . The method of  claim 19 , wherein steps a) and b) occur at different times or the same time.