Reducing the permeability of a rock formation

摘要

Permeability of a highly permeable zone in a subterranean formation is reduced by injecting an oil external emulsion of an aqueous solution of alkali metal silicate. Emulsion adjacent the well bore is broken by the application of microwave. Released alkali metal silicate then forms a plug of gel at this point, through contact with formation brines, which holds the rest of the emulsion in place until it breaks down and gels. In one aspect a second internal phase containing a gelation agent is provided to accelerate gelling.