Patent ID: 8093187

Claim:
An aqueous oilfield treatment composition comprising a viscoelastic surfactant and a co-gelling agent wherein the co-gelling agent has a structure selected from the group consisting of H(CH 2 ) x CO(OCH 2 CH 2 ) y OCO(CH 2 ) z H, HO(CH 2 CH 2 O) x′ CO(CH 2 ) y′ CO(OCH 2 CH 2 ) z′ OH, and HO(CH 2 CH 2 O) x′ (CH 2 ) y′ (OCH 2 CH 2 ) z′ OH, in which y is from about 10 to about 50, preferably from about 24 to about 36; y′ is from about 4 to about 50, preferably from about 6 to about 24; x and z are from about 6 to about 22, preferably from about 8 to about 16; and x′ and z′ are from about 1 to about 50, preferably from about 3 to about 40, and further wherein the concertration of the co-gelling agent is from about 0.005 to about 0.075%.