Patent ID: 7008908

Claim:
A method for treating a subterranean formation having at least one oil producing zone and at least one water producing zone, comprising the steps of: (a) providing a water shut-off composition to said formation, said water shut-off composition not viscosified with a viscoelastic surfactant, said water shut-off composition preferentially treating said at least one water producing zone; then (b) providing a VES fluid to said formation wherein after said providing of said VES fluid said VES fluid is substantially less viscous in the at least one oil producing zone than in the at least one water producing zone; and then (c) providing a matrix acidizing compostion to said formation, said matrix acidizing composition selected from the group consisting of an acid, a chelant, and mixtures thereof, said VES fluid in said at least one water producing zone impeding interaction of said matrix acidizing composition with said water shut-off composition, whereby said matrix acidizing composition preferentially dissolves said water shut-off composition in said oil producing zone.