Herde-aktiverte sementblandinger og fremgangsmaater

摘要

A subterranean zone is cemented using a set-activated cement composition basically comprised of water. particulate condensed silica fume suspended in the water; a dispersing agent for facilitating the dispersal of the silica fume particles in the water and maintaining the particles in suspension therein; a set-activator; and a set delaying additive for increasing the time in which the composition sets after the set-activator is combined therewith. The activator can be added last. just before the composition is pumped downhole.