Allen Joseph C, Tate Jack F, Park Jack H: Combined multiple solvent miscible flooding water injection technique for use in petroleum formations. Texaco, Ries C G, September 24, 1974: US3837399 (16 worldwide citation)

A petroleum recovery method employing a mixed solvent for use in subterranean petroleum-containing formations. The mixed solvent density is less than the density of water and greater than the density of the formation petroleum, and preferably has a boiling point less than the boiling point of the fo ...