Polymer-microemulsion complexes for the enhanced recovery of oil
AssigneeExxon Research & Engineering Co.
InventorsNathan H. Canter, Max L. Robbins, Edward G. Baker
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Abstract
A polymer-microemulsion complex useful for the enhanced recovery of crude oil 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. The polymer microemulsion complexes are stable at high salinity, reduce adsorption and retention by the formation, lower interfacial tension, achieve retentions as low as 0.1 mg surfactant/gm sand at high salinity and provide for early banking, as well as high recovery of oil.
Claims23
A stabilized microemulsion system containing a polymer-microemulsion complex which comprises:
- (a) a microemulsion, said microemulsion including 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 polymermicroemulsion complex being characterized by a complexation energy of at least 2 Kcal/mole.
A micellar formulation suitable for recovering crude oil by chemically enhanced recovery techniques which comprises
- (a) 0.3 to 98 wt.% of oil,
- (b) 1 to 99 wt.% of water containing up to 25% dissolved inorganic salts,
- (c) 0.2 to 15 wt.% of at least one anionic surfactant,
- (d) 0.1 to 10 wt.% of a polar polymer capable of forming a polymer-surfactant 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, and
- (e) 0 to 15 wt.% of cosurfactant, wherein the polar polymer and surfactant form a polymer-surfactant complex characterized by a complexation energy of at least 2 Kcal/mole.
Dependencies are inferred from the claim text.