A method of cementing a subterranean formation includes forming a cement composition comprising cementitious material, an aqueous base fluid, a nano-reinforcement particle suspension comprising a surfactant and nano-reinforcement particles such as single-wall carbon nanotubes or multi-wall carbon nanotubes; and pozzolanic material; introducing the cement composition into a subterranean formation; and allowing the cement composition to set in the subterranean formation. A method of making a cement composition includes combining cementitious material, an aqueous base fluid, a nano-reinforcement particle suspension comprising a surfactant, and a pozzolanic material, where the rate of hydration of the surfaces of the cementitious material is less retarded by the surfactant than an equivalent cement composition without pozzolanic material.

A method of cementing a subterranean formation includes forming a cement composition comprising cementitious material, an aqueous base fluid, a nano-reinforcement particle suspension comprising a surfactant and nano-reinforcement particles such as single-wall carbon nanotubes or multi-wall carbon nanotubes; and pozzolanic material; introducing the cement composition into a subterranean formation; and allowing the cement composition to set in the subterranean formation. A method of making a cement composition includes combining cementitious material, an aqueous base fluid, a nano-reinforcement particle suspension comprising a surfactant, and a pozzolanic material, where the rate of hydration of the surfaces of the cementitious material is less retarded by the surfactant than an equivalent cement composition without pozzolanic material.

A corrosion inhibiting cement composition for reducing corrosion of wellbore casings is disclosed that includes from 10 weight percent to 70 weight percent cement precursor, from 5 weight percent to 70 weight percent water, from 0.1% to 60% by weight of cement amine corrosion inhibitor, where the amine corrosion inhibitor comprises a polyethylene polyamine. A method for reducing corrosion of wellbore casings includes dispensing the corrosion inhibiting cement compositions into the annulus and allowing the corrosion inhibiting cement composition to cure to form a hardened cement, where the corrosion inhibiting cement composition includes a cement composition and the amine corrosion inhibitor.

Lost circulation material (LCM) compositions may include a resin; an emulsifier selected from the group consisting of ethoxylated phenol, sodium salt of modified tall oil fatty amide, carboxylic acid terminated fatty polyamide, modified amidoamine, tall oil fatty acid, oxidized tall oil fatty amidoamine, ether carboxylic acid, and combinations thereof; a crosslinker, a cementitious and/or weighting agent; a retarder; a dispersant; and a silicon-based defoamer. The LCM compositions may have a thickening time of from about 3 hours than about 6 hours by reaching a Bearden consistency of 100 Bc. Methods of eliminating or reducing lost circulation in a lost circulation zone from a well may include introducing these LCM compositions into the well.

A cement for use in wells in which hydrogen sulfide is present, comprises polymer particles. In the event of cement-matrix failure, or bonding failure between the cement/casing interface or the cement/borehole-wall interface, the polymer particles swell when contacted by hydrogen sulfide. The swelling seals voids in the cement matrix, or along the bonding interfaces, thereby restoring zonal isolation.

In an embodiment, the cement compositions comprise: (i) hydraulic cement, wherein the hydraulic cement has a ratio of CaO to SiO.sub.2 in the range of 2.0 to 4.0; and (ii) a water-soluble metaphosphate in a concentration of at least 2.5% bwoc. In another embodiment, the cement compositions comprise: (i) hydraulic cement, wherein the hydraulic cement has a ratio of CaO to SiO.sub.2 of less than 2.0; and (ii) a water-soluble metaphosphate; wherein any alkali nitrate is in a concentration of less than 2% bwoc; and wherein any alkali hydroxide, alkali carbonate, or alkali citrate is in a concentration of less than 0.2% bwoc. Methods of cementing in a well comprising forming either of such cement compositions and introducing it into the well are provided.

A composition of matter may include a cement precursor, a phosphazene oligomer and water. A method may include blending a phosphazene oligomer and a cement precursor to form a cement precursor mixture. The method may then include introducing water into the cement precursor mixture to form the cement slurry. A composition of matter may include a cured cement matrix having a polyphosphazene polymer distributed throughout the cement matrix. A method may include cementing a wellbore by introducing a cement slurry into a wellbore, where the cement slurry includes a phosphazene oligomer. The method then includes maintaining the cement slurry such that a cured cement sheath forms, the cement sheath having a polyphosphazene polymer.

The invention provides a high temperature resistant Portland cement slurry and a production method thereof. The high temperature resistant Portland cement slurry comprises the following components by weight: 100 parts of an oil well Portland cement, 60-85 parts of a high temperature reinforcing material, 68-80 parts of fresh water, 1-200 parts of a density adjuster, 0.1-1.5 parts of a suspension stabilizer, 0.8-1.5 parts of a dispersant, 3-4 parts of a fluid loss agent, 0-3 parts of a retarder and 0.2-0.8 part of a defoamer. The high temperature resistant Portland cement slurry has a good sedimentation stability at normal temperature, and develops strength rapidly at a low temperature. The compressive strength is up to 40 MPa or more at a high temperature of 350 C., and the long-term high-temperature compressive strength develops stably without degradation. Therefore, it can meet the requirements for field application in heavy oil thermal recovery wells, reaching the level of Grade G Portland cement for cementing oil and gas wells.

A method of cementing a wellbore penetrating a subterranean formation comprises blending a base cement slurry with one or more liquid additives to provide a cementing composition, the base cement slurry comprising a liquid carrier, a class G cement or a blend of class G and class C cements as defined by the American Petroleum Institute (API) Specification 10A standards (R2015), and silica fume, or fumed silica, or a combination of silica fume and fumed silica, the base cement slurry having a density of about 14 to about 16 ppg; and injecting the cementing composition into the wellbore. The single base cement slurry can be used globally to make cementing compositions having wide ranges of density and temperature stability.

A method of cementing a wellbore penetrating a subterranean formation comprises blending a base cement slurry with one or more liquid additives to provide a cementing composition, the base cement slurry comprising a liquid carrier, a class G cement or a blend of class G and class C cements as defined by the American Petroleum Institute (API) Specification 10A standards (R2015), and silica fume, or fumed silica, or a combination of silica fume and fumed silica, the base cement slurry having a density of about 14 to about 16 ppg; and injecting the cementing composition into the wellbore. The single base cement slurry can be used globally to make cementing compositions having wide ranges of density and temperature stability.