Dictionary:Chemically enhanced recovery
An enhanced oil recovery (q.v.) method that involves injecting polymers, surfactants, or alkaline substances to improve oil production. Polymers increase the viscosity of injected water (thickens the water) so that the water matches that of the reservoir oil as close as possible, thus making fluid flow more uniform. Surfactants break down the surface tension of oil that has collected in droplets so that it can be produced. Usually a small amount of surfactants are injected and are followed by polymer flooding and finally by untreated water. Alkaline flooding is similar to surfactant flooding except that the surfactants are generated in the reservoir by reacting with petroleum acids.