Ultra low density cementitious slurries for use in cementing of oil and gas wells

摘要

The storable, low-density, hydraulically-active, cementitious slurry of the invention is suitable for cementing within a subterranean formation for oil or gas wells. The low-density slurry comprises a hydraulically-active cementitious material, a set retarder, a plasticizer, glass or ceramic micro-spheres, and a strengthening agent. Further the slurry is substantially free of a suspension agent. The storable, low-density, hydraulically-active, cementitious slurry is made by adding glass or ceramic micro-spheres to a hydraulically-active cementitious material, adding a strengthening agent to the microsphere containing composition, and mixing the resulting composition with water, a set retarder, and a plasticizer to generate a slurry, wherein the set retarder is present in an amount sufficient to allow storage of the slurry.