Oil recovery process using polymer microemulsion complexes
AssigneeExxon Research & Engineering Co.
InventorsNathan H. Canter, Max L. Robbins, Edward G. Baker
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Abstract
A process for the enhanced recovery of oil from a subterranean formation using a polymer-microemulsion complex is disclosed. The polymer is polyethylene oxide or polyvinyl pyrrolidone and interacts with the surfactant of the microemulsion to form a physical association. The resulting complex is characterized by a complexation energy of at least 2 Kcal/mole. Slugs containing the present polymer-microemulsion complexes are stable at high salinity, show reduced destabilization due to surfactant adsorption and retention by the formation, have low interfacial tensions and achieve an early banking, as well as increased displacement of crude oil.
Claims24
A process for recovering crude oil from a subterranean formation which comprises injecting into the formation a stabilized microemulsion system which contains a polymer-microemulsion complex in an amount effective to displace oil, said microemulsion system comprising
- (a) a microemulsion containing as components
- (1) an oil,
- (2) water having up to 25% by weight of dissolved inorganic salts, and
- (3) 0.2 to 15 wt. %, based on the microemulsion, of at least one anionic surfactant balanced to form the microemulsion, and
- (b) from 0.1 to 10% by weight, based on the microemulsion of a polar polymer capable of forming a polymer-microemulsion complex wherein the polar polymer has a molecular weight of from 4,000 to 5,000,000 and is selected from the group consisting of branched polyethylene oxide condensation product of polyethylene oxide, bisphenol A and epichlorohydrin and polyvinyl pyrrolidone, the polymer-microemulsion complex being characterized by a complexation energy of at least 2 Kcal/mole, driving the microemulsion system through the formation to displace oil, and recovering the resultant crude oil.
A process for recovering crude oil from a subterranean formation which comprises injecting into the formation an aqueous solution containing from 0.25 to 5 wt. % of a polar polymer having a molecular weight of from 4,000 to 5,000,000 and selected from the group consisting of branched polyethylene oxide condensation product of polyethylene oxide, bisphenol A and epichlorohydrin and polyvinyl pyrrolidone, a microemulsion containing an oil, water having up to 25 wt. % of dissolved inorganic salts and from 0.2 to 15 wt. % of at least one anionic surfactant balanced to form the microemulsion whereby a polymer-microemulsion complex is formed in-situ, said complex being characterized by a complexation energy of at least 2 Kcal/mole, driving the polymer-microemulsion complex through the formation to displace oil and recovering the resultant oil.
A process for recovering crude oil from a subterranean formation which comprises injecting into the formation a stabilized microemulsion system which contains a polymer-microemulsion complex in an amount effective to displace oil, said microemulsion system comprising
- (a) a microemulsion containing as components
- (1) an oil,
- (2) water having up to 25% by weight of dissolved inorganic salts, and
- (3) 0.2 to 15 wt. % based on the microemulsion of at least one anionic surfactant balanced to form the microemulsion, and
- (b) from 0.1 to 10% by weight, based on the microemulsion of a polar polymer capable of forming a polymer-microemulsion complex wherein the polar polymer is a branched polyethylene oxide condensation product of polyethylene oxide, bisphenol A and epichlorohydrin having a molecular weight of from 10,000 to 500,000, the polymer-microemulsion complex being characterized by a complexation energy of from about 5 to 15 Kcal/mole, driving the microemulsion system through the formation to displace oil, and recovering the resultant crude oil.
Dependencies are inferred from the claim text.