Disclosed is a method of cementing. The method comprises providing a set-delayed cement composition comprising water, pumice, hydrated lime, a set retarder, and a micro-electrical-mechanical system; and allowing the set-delayed cement composition to set.

Disclosed is a method of spraying a surface with a set-delayed cement. The method comprises providing a set-delayed cement composition comprising water, pumice, hydrated lime, and a set retarder; spraying a surface with the set-delayed cement composition; and allowing the set-delayed cement composition to set on the surface.

Disclosed is a method of spraying a surface with a set-delayed cement. The method comprises providing a set-delayed cement composition comprising water, pumice, hydrated lime, and a set retarder; spraying a surface with the set-delayed cement composition; and allowing the set-delayed cement composition to set on the surface.

Methods of using extended-life cement compositions are disclosed. A method comprises providing an extended-life cement composition comprising calcium-aluminate cement, water, and a cement set retarder. The method additionally comprises mixing the extended-life cement composition with a cement set activator to activate the extended-life cement composition. The method further comprises Introducing the activated extended-life cement composition into a subterranean formation and allowing the activated extended-life cement composition to set in the subterranean formation; wherein the activated extended-life cement composition has a thickening time of greater than about two hours.

A method for conditioning an acid waste by cementation, wherein the acid waste is chosen among liquids having a pH of no more than 4, semi-liquids having a pH of no more than 4, solids of which the partial or full dissolution in water leads to a solution or suspension having a pH of no more than 4, and mixtures thereof, which method comprises the steps of: a) preparing a cement paste having as components at least: a magnesium phosphate cement and the acid waste, and b) hardening the cement paste thus obtained, and is characterised in that in step a), the cement paste is prepared without subjecting beforehand the acid waste to any treatment consisting in reducing the acidity thereof.

Methods and compositions for using geopolymers to create storable cementitious slurries used for oil and gas well cementing are provided. The methods of the present disclosure include providing a set-delayed geopolymer cement composition including a geopolymer; activating the set-delayed geopolymer cement composition; introducing the set-delayed geopolymer cement composition into at least a portion of a subterranean formation; and allowing the set-delayed geopolymer cement composition to set in the subterranean formation.

Methods and compositions for using geopolymers to create storable cementitious slurries used for oil and gas well cementing are provided. The methods of the present disclosure include providing a set-delayed geopolymer cement composition including a geopolymer; activating the set-delayed geopolymer cement composition; introducing the set-delayed geopolymer cement composition into at least a portion of a subterranean formation; and allowing the set-delayed geopolymer cement composition to set in the subterranean formation.

Embodiments relate to cementing operations and, in certain embodiments, to passivated cement accelerators and methods of using passivated cement accelerators in subterranean formations. An embodiment may comprise a method of cementing comprising: providing a cement composition comprising cement, water, and a passivated cement accelerator; and allowing the cement composition to set.

Embodiments relate to cementing operations and, in certain embodiments, to passivated cement accelerators and methods of using passivated cement accelerators in subterranean formations. An embodiment may comprise a method of cementing comprising: providing a cement composition comprising cement, water, and a passivated cement accelerator; and allowing the cement composition to set.

A concrete durability protection method is provided, including following steps: Step one: rinsing the concrete surface; Step two: spraying agent A material or alternately spraying agent B material and agent A material at the wet surface of the concrete; Step three: repeating step two. The beneficial effects of the present invention include: nanoscale active silicate penetrates into the concrete surface layer within a certain depth and reacts with free calcium ions within the concrete to form C—S—H crystalline, thereby improving the compactness of the concrete surface layer within a certain depth, repairing defects in the concrete surface layer within a certain depth, such as the capillary interstices, pores, microcracks, etc., so as to effectively improve the durability of concrete. The unreacted nanoscale active silicate material has permanent activity. It could recover its activity when the concrete absorbs moisture, and continue to react with free calcium ions in the concrete to quickly form C—S—H crystals, realizing the permanent concrete durability protection.