PROCEDE POUR L'EXPLOITATION SECONDAIRES DU PETROLE BRUT

摘要

Oil recovery from reservoirs having connate water containing at least 500 ppm of divalent cation is improved by first injecting an aqueous preslug containing 50 - 2,000 ppm of a biopolymer and thereafter injecting a displacement slug, preferably a micellar dispersion, followed by a mobility buffer fluid and this, in turn, followed by a water drive. The preslug containing the biopolymer "insulates" the micellar dispersion from the connate water, the divalent cation tends to degrade the micellar dispersion.