Patent ID: 9139760
Filing Date: 2015-09-22
Classification: C09D,C09K,E21B

Abstract:
1. A method of increasing the recovery of hydrocarbon fluids in a subterranean formation comprising injecting into the subterranean formation a composition comprising water, an unreacted tertiary crosslinker, and a highly cross linked expandable hydrophilic polymer particle, wherein: i) said polymer particle has an unexpanded volume average particle size diameter of 0.05-10 microns and a crosslinker content of about 9,000-200,000 ppm of labile crosslinker and about greater than 0 to 300 ppm of stable crosslinker, ii) said polymer particle has a smaller diameter than the pores of the subterranean formation, and iii) said labile crosslinkers break under the conditions of temperature and pH in the subterranean formation to allow the polymer particle to expand and said tertiary crosslinker then reacts with said polymer to form a stable gel.