| abstract |
The storable, low-density, hydraulically-active, cementitious slurry is suitable for cementing subterranean formation with oil or gas wells. The slurry comprises a hydraulically-active cementitious material, a set retarder, a plasticiser, glass or ceramic microspheres. Further, the slurry is substantially free of suspension agent. The retarder may be a hydroxycarboxylic acid, glucoheptonate, lignin sulphonate, gluconate, phosphonate or sugar. The plasticiser is preferably partially neutralised polyacrylate polymer and the strengthening agent is preferably silica fume. The slurry may be stored, and then activated when required for use. The slurry may be prepared off-site, stored and then transported to the well bore when needed. The low density of the slurry makes if useful for weak subterranean formations. |