Storable cement slurries utilize a carrageenan suspending agent to provide stable slurries under conditions of high pH and calcium ion content. These cement slurries may be utilized for, among other things, cementing applications involving oil and gas wells.
The present application claims priority on the co-pending provisional U.S. patent application Ser. No. 60/048,718 filed May 28, 1997. The entire text of the above-referenced disclosures is specifically incorporated by reference herein without disclaimer.
A cement composition for liquid casting, based on a binder comprising Portland cement and additives comprising at least a fluidizer and a combination of a thickening agent acting by steric exclusion and a gelling thickening agent. The composition can also include a surface active agent to regulate the quantity of entrained air. Mixed with water and an aggregate, it permits obtaining, in a single casting, a self-leveling casting of a high thickness (equal to at least 6 cm) and of low density (about 1.6 to 1.9).
Storable compositions and slurries for cementing oil and gas wells are described which comprise blast-furnace slag besides other additives which are usual in the cementing technique. The compositions and slurries are insufficiently activated (or are activated immediately before introducing them into the well), so that they can be stored for at least 72 hours (alternatively they may be stored indefinitely) without the setting of the composition and dispense with the addition of activation inhibitors. The use of the compositions and slurries in the cementing of oil and gas wells is also described.
Storable compositions and slurries for cementing oil and gas wells are described which comprise blast-furnace slag besides other additives which are usual in the cementing technique. The compositions and slurries are insufficiently activated (or are activated immediately before introducing them into the well), so that they can be stored for at least 72 hours (alternatively they may be stored indefinitely) without the setting of the composition and dispense with the addition of activation inhibitors. The use of the compositions and slurries in the cementing of oil and gas wells is also described.
The present invention provides methods, lightweight well cement compositions and additives for the well cement compositions. The methods of the invention for sealing pipe in a well bore penetrating a zone or formation which readily fractures at low hydrostatic pressure is basically comprised of the steps of providing a lightweight cement composition comprised of a hydraulic cement, water and an additive comprising a suspension of microspheres in water gelled with sodium bentonite, placing the cement composition in the annulus between the pipe and the well bore and allowing the cement composition to set.
A storable cement system comprises a suspending agent, a cement spacer and water. The composition may further optional contain a surfactant and/or an organic solvent and/or a weighting material. The suspending agent is preferably a carrageenan or scleroglucan. The cement system may be stored for an extended period of time prior to being interposed between a cement slurry and a drilling fluid. As such, the aqueous cement system may be made off-site and used when desired for preventing contact between non-compatible hydrocarbonaceous and aqueous fluids.
