Oil recovery technique:
Enhanced oil recovery (EOR) is used to increasing the amount of crude oil that can be
extracted from an oil field. Enhanced
oil recovery is also called tertiary recovery (as opposed to primary and secondary recovery). According to
the US Department of Energy, there are three primary techniques for EOR:
thermal recovery, gas injection, and chemical injection. Sometimes the
term quaternary recovery is used to refer to more advanced, speculative, EOR
techniques in oil field.