Patent ID: 6454004
Filing Date: 2002-09-24
Classification: C04B,C09K,Y10S

Abstract:
An improved method of cementing a casing string in a deep water offshore formation penetrated by a well bore comprising the steps of:(a) preparing a cement composition comprised of a single hydraulic cement, sufficient water to form a pumpable slurry, an environmentally degradable water reducing and dispersing additive, an environmentally degradable set retarding additive selected from the group consisting of sodium lignosulfonate, calcium lignosulfonate and ammonium lignosulfonate, said set retarding additive being present in an amount in the range of from about 0.0165% to about 0.165% by weight of cement in said composition, and an environmentally degradable compressive strength and set accelerating additive; (b) placing said cement composition in the annulus between said casing and said well bore; and (c) allowing said cement composition to set into a hard impermeable mass therein.