Encapsulated Fluid-Loss Additives for Cement Compositions

摘要

Methods and compositions for cementing in a subterranean formation. An example method of cementing comprises providing a cement composition comprising a hydraulic cement, water, and an encapsulated fluid-loss additive; wherein the encapsulated fluid-loss additive comprises a fluid-loss additive and an encapsulation material; placing the cement composition in a selected location; and allowing the cement composition to set.

主权项

1. A method of cementing comprising:
providing a cement composition comprising:
a hydraulic cement,water, andan encapsulated fluid-loss additive; wherein the encapsulated fluid-loss additive comprises a fluid-loss additive in an amount of about 60% to about 99.9% by weight of the encapsulated fluid-loss additive and an encapsulation material in an amount of about 0.1% to about 40% by weight of the encapsulated fluid-loss additive; wherein the fluid-loss additive is encapsulated by matrix encapsulation; placing the cement composition in a selected location; and allowing the cement composition to set; wherein the encapsulation material delays release of the fluid-loss additive into the cement composition for a time of about 5 minutes to about 30 minutes.