Compositions and methods for well completions

摘要

Incorporation of carbonaceous materials in a cement slurry increases the linear thermal- expansion coefficient of the set cement. When placed in a subterranean well having at least one casing string, cement sheaths with linear thermal-expansion coefficients similar to that of the casing will be subjected to lower compressive and tensile stresses during downhole-temperature changes. Such cement slurries are particularly advantageous in the context of thermal -recovery wells.