Microbial-enhanced well cementing and remediation

摘要

Described are a method and composition which use microorganisms for downhole applications, in particular for the maintenance or restoration of the integrity of a cement sheath in a wellbore. The method of cementing a wellbore comprises preparing a cement composition comprising a pumpable slurry of cement, water and a healing agent that comprises one or more microorganisms, delivering the cement composition into the wellbore and allowing the cement composition to set. The method of restoring the integrity of a set cement composition in a wellbore comprises preparing a pumpable slurry that comprises water, a healing agent that comprises one or more microorganisms and optionally cement, pumping the slurry into the wellbore in and around the set cement composition, and allowing the one or more microorganisms to grow and replicate to thereby restore the integrity of the set cement composition. Compositions for carrying out the methods are also described.