A method of making a cement composite can include contacting an aqueous solution comprising calcium ions with a carbon dioxide source producing a carbonated aqueous solution. Fine particles can be submerged in the carbonated aqueous solution to produce microaggregate particles comprising the fine particles coated with calcium carbonate. The microaggregate particles can be combined with cement particles to produce the cement composite. The cement composite can be used in cementing applications for hydrocarbon wells including for casing liners and well plugs.

This invention relates to using a unique blend of components of a composite cement and subjecting them to a rotary mill process using variably sized and shaped media to reduce the blends' particle size. The invention is novel in that it mills the blended materials together to achieve reduced particle size, increased particle surface area, higher compressive strength and lower permeability. In one embodiment, the invention combines fly ash or other pozzolan material with a cement of any type at varying rations between 1% and 99%. In a further embodiment the invention combines fly ash or other pozzolan material at 60% with a cement of any type at 40%.

Portland cement clinker LCMs that include Portland cement clinker to mitigate or prevent lost circulation in a well are provided. A Portland cement clinker LCM may include Portland cement clinker, Portland cement, a carrier fluid, and an inorganic consolidation activator. Another Portland cement clinker LCM may include Portland cement clinker and a crosslinked fluid, such as a polyuronide crosslinked via calcium ions or a polysaccharide crosslinked via divinyl sulfone. Yet another Portland cement clinker LCM may include Portland cement clinker and polymer fibers or particulate glass. Methods of lost circulation control using a Portland cement clinker LCM are also provided.

Portland cement clinker LCMs that include Portland cement clinker to mitigate or prevent lost circulation in a well. A Portland cement clinker may include Portland cement clinker, Portland cement, a carrier fluid, and an inorganic consolidation activator. Another Portland cement clinker LCM may include Portland cement choker and a crosslinked fluid, such as a polyuronide crosslinked via calcium ions or a polysaccharide crosslinked via divinyl sulfone. Yet another Portland cement clinker may include Portland cement clinker and polymer fibers or particulate glass. Methods of lost circulation control using a Portland cement clinker LCM are also provided.

A method of treating a subterranean formation comprising: introducing a first cement composition into the subterranean formation, wherein the first cement composition comprises: (A) a first aluminate cement; and (B) a base fluid; simultaneously introducing a second cement composition into the subterranean formation, wherein the second cement composition comprises: (A) a second cement consisting of cement or a pozzolan; and (B) a base fluid, wherein at least a portion of the first and second cement compositions mix together after introduction into the subterranean formation to form a mixed cement composition, and wherein at least some of the first and second cement compositions or at least some of the mixed cement composition enters into a highly-permeable area located within the subterranean formation; and allowing the mixed cement composition to set. The base fluid can be an aqueous liquid or a hydrocarbon liquid.

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.

Portland cement clinker LCMs that include Portland cement clinker to mitigate or prevent lost circulation in a well are provided. A Portland cement clinker LCM may include Portland cement clinker, Portland cement, a carrier fluid, and an inorganic consolidation activator. Another Portland cement clinker LCM may include Portland cement clinker and a crosslinked fluid, such as a polyuronide crosslinked via calcium ions or a polysaccharide crosslinked via divinyl sulfone. Yet another Portland cement clinker LCM may include Portland cement clinker and polymer fibers or particulate glass. Methods of lost circulation control using a Portland cement clinker LCM are also provided.

Portland cement clinker LCMs that include Portland cement clinker to mitigate or prevent lost circulation in a well are provided. A Portland cement clinker LCM may include Portland cement clinker, Portland cement, a carrier fluid, and an inorganic consolidation activator. Another Portland cement clinker LCM may include Portland cement clinker and a crosslinked fluid, such as a polyuronide crosslinked via calcium ions or a polysaccharide crosslinked via divinyl sulfone. Yet another Portland cement clinker LCM may include Portland cement clinker and polymer fibers or particulate glass. Methods of lost circulation control using a Portland cement clinker LCM are also provided.

Portland cement clinker LCMs that include Portland cement clinker to mitigate or prevent lost circulation in a well are provided. A Portland cement clinker LCM may include Portland cement clinker, Portland cement, a carrier fluid, and an inorganic consolidation activator. Another Portland cement clinker LCM may include Portland cement clinker and a crosslinked fluid, such as a polyuronide crosslinked via calcium ions or a polysaccharide crosslinked via divinyl sulfone. Yet another Portland cement clinker LCM may include Portland cement clinker and polymer fibers or particulate glass. Methods of lost circulation control using a Portland cement clinker LCM are also provided.

Portland cement clinker LCMs that include Portland cement clinker to mitigate or prevent lost circulation in a well are provided. A Portland cement clinker LCM may include Portland cement clinker, Portland cement, a carrier fluid, and an inorganic consolidation activator. Another Portland cement clinker LCM may include Portland cement clinker and a crosslinked fluid, such as a polyuronide crosslinked via calcium ions or a polysaccharide crosslinked via divinyl sulfone. Yet another Portland cement clinker LCM may include Portland cement clinker and polymer fibers or particulate glass. Methods of lost circulation control using a Portland cement clinker LCM are also provided.