Oil recovery from oil-bearing formations - by injection of an aq. emulsion of an oil solvent

摘要

In a process for recovering oil (esp. residual oil) from an oil-bearing formation, an aq. emulsion of one or more solvents for the oil is injected into the formation and the resulting soln. of oil in the solvent(s) recovered. Working costs and solvent losses are less than when pure solvent is used, and more viscous oil residues can be recovered than in the case water or steam injection; the process is esp. applicable to tar sands. The solvent is pref. a light petroleum fraction, but can also be an aromatic solvent, turpentine and/or white spirit. The emulsifier is pref. nonionic. The solvent concn. in the emulsion is pref. 1-50%. The emulsion pref. also contains LPG to increase its rising power and facilitate sepn. of the solvent phase.