Patent ID: 7533723

Claim:
A method of reducing the outflow of water during recovery of hydrocarbons from a hydrocarbon reservoir in a formation, comprising: (a) providing a non-aqueous well bore treatment fluid based on a liquid selected from oil or a mixture of oil and solvent such that said treatment fluid is not fully miscible with water, said treatment fluid containing 5 to 40 weight per cent of a water-immiscible dissolved compound based on α-branched carboxylic acid, derivatives or co-polymers thereof, and capable of forming a precipitate that is soluble in hydrocarbons and insoluble in water, and (b) injecting said non-aqueous treatment fluid into a well bore; and (c) letting the non-aqueous fluid permeate formation surrounding the well bore (d) causing or allowing water or brine to mix with the non-aqueous fluid within the formation, to form a said precipitate therein and reduce the outflow of water therefrom.