Abstract: A cement composition comprises: cement; water; and an additive, wherein the additive is a pozzolan and a strength-retrogression inhibitor, and wherein a mixture consisting essentially of: the additive; water; and a source of calcium develops a compressive strength of at least 500 psi at a time of 24 hours, a temperature of 190° F., and a pressure of 3,000 psi. A method of cementing in a subterranean formation comprises: introducing the cement composition into the subterranean formation and allowing the cement composition to set. The compressive strength of the test cement composition consisting essentially of: the cement; the water; and the additive at a final time of 72 hours has a percent change greater than ?5% from the compressive strength of the test cement composition at an initial time of 24 hours when tested at a temperature of 300° F. and a pressure of 3,000 psi.

Abstract: A cement composition comprises: cement; water; and an additive, wherein the additive is a pozzolan and a strength-retrogression inhibitor, and wherein a mixture consisting essentially of: the additive; water; and a source of calcium develops a compressive strength of at least 500 psi at a time of 24 hours, a temperature of 190° F., and a pressure of 3,000 psi. A method of cementing in a subterranean formation comprises: introducing the cement composition into the subterranean formation and allowing the cement composition to set. The compressive strength of the test cement composition consisting essentially of: the cement; the water; and the additive at a final time of 72 hours has a percent change greater than ?5% from the compressive strength of the test cement composition at an initial time of 24 hours when tested at a temperature of 300° F. and a pressure of 3,000 psi.