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: A retarder aid increases the applicable temperature range of phosphonate/borate cement-retarder systems to at least 302° C. (575° F.), and 207 MPa (30,000 psi). The retarder aid comprises a terpolymer of styrene sulfonate, maleic anhydride and acrylate of ethylene oxide. Cement slurries containing the retarder and retarder aid may be used for both primary-cementing and remedial-cementing applications.

Abstract: Well-cementing compositions for use in high-pressure, high-temperature (HPHT) wells are often densified, and contain weighting agents such as hematite, ilmenite, barite and hausmannite. The weighting agents are usually finely divided to help keep them suspended in the cement slurry. At high temperatures, finely divided weighting agents based on metal oxides react with the calcium-silicate-hydrate binder in set Portland, cement, leading to cement deterioration. Finely divided weighting agents based on metal sulfates are inert with respect to calcium silicate hydrate; consequently, set-cement stability is preserved.

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: 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: Cementing compositions for use in oilfield applications are designed such that, after setting, a significant amount of cement remains unhydrated. After placement in a subterranean well, the unhydrated cement remains dormant. If the cement sheath becomes damaged, the unhydrated cement hydrates upon exposure to formation fluids, thereby restoring zonal isolation in the wellbore. The compositions comprise emulsions that allow a substantial reduction of the water-to-cement ratio, yet the rheological properties remain suitable for placement in the well.

Abstract: The present invention provides means to seal voids and cracks in subterranean-formation rock that contains carbonate minerals, thereby minimizing or stopping fluid flow between the formation rock and the wellbore of a subterranean well. The methods comprise pumping a solution of one or more lattices that contain at least one carboxylated monomer down a well and allowing it to enter voids (e.g., pores, fractures, vugs and caverns) in the carbonate-containing formation, whereupon it reacts with divalent cations liberated by the carbonates and forms a gel.

Abstract: Well-cementing compositions for use in high-pressure, high-temperature (HPHT) wells are often densified, and contain weighting agents such as hematite, ilmenite, barite and hausmannite. The weighting agents are usually finely divided to help keep them suspended in the cement slurry. At high temperatures, finely divided weighting agents based on metal oxides react with the calcium-silicate-hydrate binder in set Portland cement, leading to cement deterioration. Finely divided weighting agents based on metal sulfates are inert with respect to calcium silicate hydrate; consequently, set-cement stability is preserved.

Abstract: Disclosed are pumpable-fluid compositions and methods for establishing hydraulic isolation in cemented subterranean wells. The fluid compositions comprise solids-free solutions of water-soluble polymers. Upon entering voids and cracks in the cement sheath and contacting the set-cement surfaces, the fluid gels and forms a seal that prevents further leakage.

Abstract: A sealant composition, 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, is useful for sealing cracks, fissures and voids in subterranean wells, thereby restoring zonal isolation. The mean particle size of the calcium containing compound is preferably smaller than 100 nm.

Abstract: A retarder aid increases the applicable temperature range of phosphonate/borate cement-retarder systems to at least 302° C. (575° F.), and 207 MPa (30,000 psi). The retarder aid comprises a terpolymer of styrene sulfonate, maleic anhydride and acrylate of ethylene oxide. Cement slurries containing the retarder and retarder aid may be used for both primary-cementing and remedial-cementing applications.

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 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: An additive for Portland-cement slurries comprises a liquid silicate absorbed into a solid porous medium. The additive is incorporated in slurries designed for well-cementing applications. The liquid silicate functions as a retarder aid and dispersant when added to slurries for use at temperatures above about 85° C. The resulting solid product allows use of the liquid silicate in well-cementing operations as if it were a dry additive.

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: A cement slurry composition for cementing a well comprising: a hydraulic cement, water and a combination made of a hydroxyethyl cellulose and an acrylamido-methyl-propane sulfonate-acrylamide copolymer. Provided is also a method for cementing a well involving such cement slurry composition. The composition provides a solution to decouple the fluid-loss control and the slurry rheologyfor cement for slurry and particularly for extended cement slurry.

Abstract: This invention relates to methods for servicing subterranean wells, in particular, fluid compositions and methods for remedial operations during which the fluid compositions are pumped into a wellbore and make contact with well cements placed during primary cementing or previous remedial cementing operations.

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: 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.