Abstract: The use of silicate as a retarder enhancer at appropriate levels to enhance the retarding effect of retarders at high temperatures encountered downhole while accelerating the set of cement at lower temperatures encountered near to the surface.

Abstract: The invention provides a cementing composition for use in oilfield application, wherein a significant amount of cement is left intentionally un-hydrated when the cement is set; such that said amount of un-hydrated cement becomes hydrated when the set cement is damaged.

Abstract: A cement retarder system for use in underground wells included a borate compound, an organophosphonate salt, and a copolymer formed from AMPS and a monomer selected from the group consisting of acrylic acid, acrylamide and mixtures thereof.

Abstract: The use of silicate as a retarder enhancer at appropriate levels to enhance the retarding effect of retarders at high temperatures encountered downhole while accelerating the set of cement at lower temperatures encountered near to the surface.

Abstract: It is proposed a new fluid loss control agent useful for the cementation of oil or gas wells. This fluid loss control agent consists of a mixture of a styrene-butadiene latex and a high molecular weight water-soluble polymer such as a copolymer AMPS-Am. The addition of the water-soluble polymer allows drastic reduction of the quantity of latex required to achieve fluid loss control performance and even gas migration control.

Abstract: The invention discloses a cement slurry composition for cementing a well comprising: an hydraulic cement, water and a combination made of a hydroxyethyl cellulose and an acrylamido-methyl-propane sulfonate-acrylamide copolymer.

Abstract: A sealant composition for use in subterranean wells comprising an alkali metal silicate and a calcium containing inorganic compound wherein the particles of the calcium containing compound have a mean particle size that is submicron.

Abstract: The present invention provides a versatile additive for improving the properties of a cement slurry made with portland cement and to be utilized in well cementing, said versatile additive comprising type of silicates and/or borates that inhibit gelation occurring with the interstitial phase. The additive of the present invention improves significantly the rheology (i.e., strong dispersing effect) and can even overcome severe gelation problems. At temperature above about 88° C. (190° F.) the additive acts as retarder aid, enabling to reduce considerably the concentration of retarder required to achieve a given thickening time.

Abstract: A cement retarder system for use in underground wells included a borate compound, an organophosphonate salt, and a copolymer formed from AMPS and a monomer selected from the group consisting of acrylic acid, acrylamide and mixtures thereof.

Abstract: The use of silicate as a retarder enhancer at appropriate levels to enhance the retarding effect of retarders at high temperatures encountered downhole while accelerating the set of cement at lower temperatures encountered near to the surface.

Abstract: The present invention provides a cementing composition for an oil well or the like with porosity of less than 50%, and with a solid phase constituted by 35% to 65% (by volume) hollow microspheres, 20% to 45% Class G Portland cement, and 5% to 25% of Class G Portland micro-cement. The invention is used to cement conductor pipes in arctic zones or in deep water holes.

Abstract: The present invention concerns a cementing composition for an oil (or similar) well, based on an aluminous hydraulic cement, fine particles, hollow microspheres, water in a quantity such that the porosity is in the range 25% to 50%, a dispersing agent, a setting accelerator for the aluminous cement and optionally, other conventional additives. The invention is of particular application to cementing conductor pipes in arctic zones or in deep-water wells.