| abstract |
The invention is directed to long lasting crosslinked water-soluble swellable polymers, methods for making same, and their uses. More particularly, the invention relates to a composition comprising expandable polymeric particles having cationic sites as well as labile crosslinkers and stable crosslinkers, said particle mixed with a fluid. A particularly important use is as an injection fluid in petroleum production, where the expandable polymeric particles are injected into a target zones in the reservoirs and when the heat and/or pH of the reservoir cause degradation of the labile crosslinker and when the particle expands, the cationic sites in the polymer adsorb to the rock in the formation, thus diverting water to lower permeability regions and improving oil recovery. However, many other uses are possible. |