Patent ID: 8183184

Claim:
A composition for controlling the release of an oil and gas field chemical comprising: a polyanion and a polycation forming a polyelectrolyte complex, said polyelectrolyte complex having a polymeric core and polymeric shell, and an oil and gas field chemical associated with said polyelectrolyte complex, wherein said composition is injected into an oil and gas well for the controlled release of the oil and gas field chemical from said complex, and wherein said oil and gas field chemical is selected from the group consisting of a scale inhibitor; which is selected from the group consisting polyvinyl sulphonic acid, hexamethylene diamine tetrakis (methylene phosphonic acid), diethylene triamine tetra (methylene phosphonic acid), diethylene triamine penta (methylene phosphonic acid), bis-hexamethylene triamine pentakis (methylene phosphonic acid), phosphino carboxylic acid, diglycol amine phosphonate, 1-hydroxyethylidene, 1,1-diphosphonate, and bisaminoethylether phosphonate; and their alkali metal salts; and wherein said polyelectrolyte complex is a nanoparticle having a particle size less than about 5000 nm.