Patent ID: 8765647

Claim:
A chemical agent for reducing water production from subterranean zones surrounding oil and gas wells, the chemical agent comprising polymeric, cross-linked particles which are stable in water-free solvents, wherein: a) the particles are manufactured in an oil-in-oil emulsion and are cross-linked with at least one water-stable cross-linker and at least one water-labile cross-linker, the water-labile cross-linker being chosen among cross-linkers able to, when opened in a reaction with water, form a hydrophilic seat which increases the particles' water-swelling ability, and that b) the particles comprise at least one solid, water soluble immobilized chemical compound that, by means of the reaction between the labile cross-linker and water, forms a new chemical bonding to another particle, to another reactive seat in the same particle, or to other of said immobilized chemical compounds.