Patent ID: 7913759

Claim:
A method for recovering oil from a reservoir by waterflooding, comprising: (a) introducing an aqueous flooding fluid into the reservoir, wherein at least one portion of said flooding fluid comprises vinyl alcohol and vinyl acetate and one or more ionic polyvinyl alcohol copolymers, said one or more ionic polyvinyl alcohol copolymers comprising: (i) one or more anionic comonomers present at a total of about 1 to about 5 mol % relative to the combined moles of vinyl alcohol and vinyl acetate; (ii) optionally, one or more non-ionic comonomers present at about 0 to about 7 mol % relative to the combined moles of vinyl alcohol and vinyl acetate; wherein the total monomers in (i) and (ii) are present at less than or equal to about 8 mol %; wherein the hydrolysis level of the one or more ionic polyvinyl alcohol copolymers is greater than or equal to about 90%; and wherein the one or more ionic polyvinyl alcohol copolymers dissolves substantially completely in water at about 25° C. within about 14 hours; and (b) displacing oil in the reservoir with said flooding fluid into one or more production wells, whereby the oil is recoverable.