Patent ID: 9540574
Date: 2017-01-10
CPC Classifications: C09K,C10G,E21B

Claim:
1. A process for producing oil, comprising contacting a source water having a total dissolved solids content of at least 10,000 ppm with a first ionic filter which first ionic filter is a nanofiltration membrane, a reverse osmosis membrane or a forward osmosis membrane; passing a portion of the source water through the first ionic filter to form a permeate having reduced salinity relative to the source water while excluding at least a portion of the source water from passing through the first ionic filter to form a primary retentate having increased salinity relative to the source water due to passing the portion of the source water through the first ionic filter; passing a portion of the permeate through one or more second ionic filters wherein the one or more second ionic filters are selected from the group consisting of a nanofiltration membrane, a reverse osmosis membrane, a forward osmosis membrane and combinations thereof, to form a treated water having reduced salinity relative to the permeate while excluding at least a portion of the permeate from passing through the one or more second ionic filters to form one or more secondary retentates having increased salinity relative to the permeate due to passing the portion of the permeate through the one or more second ionic filters; utilizing the treated water as at least a portion of an aqueous fluid injected into the formation which aqueous fluid has an ionic strength of at most 0.15 M and a total dissolved solids content of from 200 ppm to 10,000 ppm into an oil-bearing formation; producing oil and water from the formation subsequent to the introduction of the aqueous fluid into the formation; mixing a demulsifier and a brine solution having a total dissolved solids content of greater than 10,000 ppm with at least a portion of the oil and water produced from the formation wherein at least a portion of the brine solution is primary retentate, one or more of the secondary retentates, or a combination of the primary retentate and one or more of the secondary retentates; and separating oil from the mixture of oil, water, demulsifier, and brine solution.