Water-flooding of oil-bearing strata - by successive injection of slugs of salt emulsifier and salt solns

摘要

Oil is extracted from underground formations by successive injection a (A) a slug of an aq. soln. of salt and surfactant with salt content giving optimum emulsification, which is higher than the salt content, which gives minimum surface tension between the soln. and the oil, (B) slug of aq. salt soln. with salt content giving optimum surface tension, and (C) a propellant fluid to drive (A) and (B) to the prodn. borehole. More complete and earlier extn. of oil from the formation is achieved.