According to one or more embodiments of the present disclosure, a cement slurry includes cement particles, an aqueous fluid in an amount of from 10 wt. % to 70 wt. % relative to the total weight of the cement particles, and a clay stabilizer consisting of one or more polyethylene polyamines having a first structure H.sub.2NCH.sub.2CH.sub.2(NHCH.sub.2CH.sub.2).sub.xNH.sub.2, where x is an integer greater than or equal to 3. The amount of the clay stabilizer may be from 1 wt. % to 10 wt. % relative to the total weight of the cement particles. The average molecular weight of the polyethylene polyamines in the cement slurry having the first chemical structure may be from 200 g/mol to 400 g/mol. All of the polyethylene polyamines in the cement slurry having the first chemical structure may be encompassed in the clay stabilizer. Methods for cementing a casing in a wellbore using the cement slurry are also disclosed.

This invention relates to a solidifying agent for solidifying radioactive waste, and more particularly to a solidifying-agent composition for solidifying radioactive waste, including alumina cement and a gypsum powder. The solidifying-agent composition including alumina cement and a gypsum powder is capable of effectively minimizing an increase in the volume of a solidified radioactive waste product to a level satisfying physical and chemical safety regulations upon the solidification of radioactive waste.

This invention relates to a solidifying agent for solidifying radioactive waste, and more particularly to a solidifying-agent composition for solidifying radioactive waste, including alumina cement and a gypsum powder. The solidifying-agent composition including alumina cement and a gypsum powder is capable of effectively minimizing an increase in the volume of a solidified radioactive waste product to a level satisfying physical and chemical safety regulations upon the solidification of radioactive waste.

Methods and compositions for treating a subterranean formation with salt-tolerant cement slurries including treating a salt-containing subterranean formation having sodium salts, potassium salts, magnesium salts, calcium salts, or any combination thereof comprising: providing a salt-tolerant cement slurry comprising: a base fluid, a cementitious material, a pozzolanic material, a salt-tolerant fluid loss additive, a salt additive, and optionally, an elastomer, a weight additive, a fluid loss intensifier, a strengthening agent, a dispersant, or any combination thereof; introducing the salt-tolerant cement slurry into the subterranean formation; and allowing the salt-tolerant cement slurry to set.

Methods and compositions for treating a subterranean formation with salt-tolerant cement slurries including treating a salt-containing subterranean formation having sodium salts, potassium salts, magnesium salts, calcium salts, or any combination thereof comprising: providing a salt-tolerant cement slurry comprising: a base fluid, a cementitious material, a pozzolanic material, a salt-tolerant fluid loss additive, a salt additive, and optionally, an elastomer, a weight additive, a fluid loss intensifier, a strengthening agent, a dispersant, or any combination thereof; introducing the salt-tolerant cement slurry into the subterranean formation; and allowing the salt-tolerant cement slurry to set.

The invention provides a low density cement composition. The composition includes a cement component, a glass sphere component, a bentonite component, a fine calcium carbonate component, a medium calcium carbonate component, a silica sand component, and a silica flour component.

The invention provides a low density cement composition. The composition includes a cement component, a glass sphere component, a bentonite component, a fine calcium carbonate component, a medium calcium carbonate component, a silica sand component, and a silica flour component.

Corrosion-resistant refractory binder compositions may be formed with a calcium ion source, high-alumina refractory aluminosilicate pozzolan, and water. Any one or more of such components may individually be non-cementitious. Examples of high-alumina refractory aluminosilicate pozzolan include crushed firebrick; firebrick grog; and mixtures of silicate and any one or more of corundum, high-alumina ceramic, and bauxite; refractory mortar; fire clay; mullite; fused mullite; and combinations thereof, among others. A binder composition may be mixed with sufficient amount of water to form a slurry, which slurry may be introduced into a subterranean formation (e.g., via a wellbore penetrating the subterranean formation). A plurality of the non-cementitious components may react in the presence of water when exposed to suitable conditions so as to enable the binder composition to set. Such compositions, once set, may exhibit enhanced corrosion and/or heat resistance as compared to other binder compositions.

Corrosion-resistant refractory binder compositions may be formed with a calcium ion source, high-alumina refractory aluminosilicate pozzolan, and water. Any one or more of such components may individually be non-cementitious. Examples of high-alumina refractory aluminosilicate pozzolan include crushed firebrick; firebrick grog; and mixtures of silicate and any one or more of corundum, high-alumina ceramic, and bauxite; refractory mortar; fire clay; mullite; fused mullite; and combinations thereof, among others. A binder composition may be mixed with sufficient amount of water to form a slurry, which slurry may be introduced into a subterranean formation (e.g., via a wellbore penetrating the subterranean formation). A plurality of the non-cementitious components may react in the presence of water when exposed to suitable conditions so as to enable the binder composition to set. Such compositions, once set, may exhibit enhanced corrosion and/or heat resistance as compared to other binder compositions.

Cementing compositions containing a hydraulic cement, halloysite nanoparticles, and silica flour. The cementing compositions may optionally include other additives such as a friction reducer, a defoamer, and a fluid loss additive. Cement samples made therefrom and methods of producing such cement samples are also specified. The addition of halloysite nanoparticles and silica flour provides enhanced mechanical strength (e.g. compressive strength, flexural strength) and improved durability (e.g. resistance to CO.sub.2 and salinity) to the cement, making them suitable cementing material for oil and gas wells.