| abstract |
Expandable and hydrophilic polymeric particles may be made in a non-emulsion system, and with controllable hardness and delay in their time to swell in a fresh or salt water environment. These particles are prepared from combining monomers, controlled monomers, stable cross-linkers, initiators, and other agents, in aqueous solution. The controlled monomers induce kinetically controllable decomposition, degrading over time, thus inducing a desired time delay in particle swelling. The delay and degree of the swelling of the particles is controlled by selection of controlled monomer, stable cross-linking agents, monomers, and process conditions. These preformed particle gels are made to an initial particle size of 0.1 micron in diameter or larger via different grinding techniques. This composition is used for modifying the permeability of subterranean formations and thereby increasing the recovery rate of hydrocarbon fluids present in the formation. |