04913235 is referenced by 27 patents and cites 14 patents.

A method of increasing the viscosity of CO.sub.2 at least three-fold by adding (1) a viscosifying amount of a polymer having a Minimum Solubility Parameter of 6.85 or less and a plurality of electron donor atoms selected from the group consisting of O, N, and S, and (2) a sufficient amount of a cosolvent to form a one-phase solution, said cosolvent being capable of (a) dissolving at least 2% by weight of CO.sub.2 at 25.degree. C. and 900 psig, and (b) forming a one-phase mixture with the polymer when the mixture contains 10 weight percent cosolvent at ambient temperature and a pressure sufficient to maintain the cosolvent in the liquid phase. New compositions containing CO.sub.2, the defined polymer and cosolvent are also claimed as is a method for recovering oil from underground formations using a viscosified CO.sub.2.

Title
Enhanced oil recovery using CO.sub.2 flooding
Application Number
749479
Publication Number
4913235
Application Date
July 14, 1987
Publication Date
April 3, 1990
Inventor
Wayne R Pretzer
Wheaton
IL, US
Cyrus A Irani
Hacienda Heights
CA, US
Thomas V Harris
Benicia
CA, US
Agent
Ernest A Schaal
Edward J Keeling
Assignee
Chevron Research Company
CA, US
IPC
E21B 43/22
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