Patent ID: 6955222
Filing Date: 2005-10-18
Classification: B01D,E21B

Abstract:
1. A method for the secondary recovery of petroleum from a location below a body of seawater by flooding a permeable petroleum-bearing stratum, which method comprises treating seawater from said body at a temperature between about 22° C. and about 75° C. to remove at least about 99% of all divalent anions and to simultaneously increase the chloride ion content of said seawater by at least 10% by pumping said seawater on a single pass through a nanofiltration membrane formed of a polyamide film created by the condensation reaction of a piperazine and an acyl chloride which film is supported upon a porous film of a different polymeric material, and then pumping said treated seawater under pressure into said permeable stratum.