A cement slurry composition, containing hydraulic cement, water, and from 1 to less than 4% of an organically modified nanoclay. A method for cementing a high pressure high temperature well by pumping the cement composition of claim 1 between a casing and a formation of a well bore to fill a gap between the casing and the formation, and allowing the cement to harden.

A cement slurry composition, containing hydraulic cement, water, and from 1 to less than 4% of an organically modified nanoclay. A method for cementing a high pressure high temperature well by pumping the cement composition of claim 1 between a casing and a formation of a well bore to fill a gap between the casing and the formation, and allowing the cement to harden.

A coating process comprising applying to a surface a coating composition consisting essentially of an alkali metal silicate and an aqueous liquid phase having dispersed therein solid aluminum particles to form on the surface a wet coating; and drying said wet coating: under conditions which convert said wet coating to an electrically conductive, corrosion-resistant, solid coating; or under conditions which form a solid coating which is not electrically conductive (non-conductive) and thereafter treating said non-conductive coating under conditions which convert said non-conductive coating to an electrically conductive, corrosion-resistant coating.

A coating process comprising applying to a surface a coating composition consisting essentially of an alkali metal silicate and an aqueous liquid phase having dispersed therein solid aluminum particles to form on the surface a wet coating; and drying said wet coating: under conditions which convert said wet coating to an electrically conductive, corrosion-resistant, solid coating; or under conditions which form a solid coating which is not electrically conductive (non-conductive) and thereafter treating said non-conductive coating under conditions which convert said non-conductive coating to an electrically conductive, corrosion-resistant coating.

A well cementing composition comprises water, an inorganic cement, a gas generating agent and a gas stabilizer. The gas generating agent may contain materials that release hydrogen gas, carbon dioxide gas or nitrogen gas or combinations thereof. The gas stabilizer comprises an aqueous mixture comprising polyglycols, oxyalkylates and methanol, or coco trimethyl ammonium chloride, or a mixture comprising ammonium fatty alcohol ether sulfate and ethylene glycol monobutyl ether, or combinations thereof. When used to cement a subterranean well, the compositions improve the compressive strength, increase the rate at which compressive strength develops, preserve cement homogeneity, or enhance cement expansion or a combination thereof.

A well cementing composition comprises water, an inorganic cement, a gas generating agent and a gas stabilizer. The gas generating agent may contain materials that release hydrogen gas, carbon dioxide gas or nitrogen gas or combinations thereof. The gas stabilizer comprises an aqueous mixture comprising polyglycols, oxyalkylates and methanol, or coco trimethyl ammonium chloride, or a mixture comprising ammonium fatty alcohol ether sulfate and ethylene glycol monobutyl ether, or combinations thereof. When used to cement a subterranean well, the compositions improve the compressive strength, increase the rate at which compressive strength develops, preserve cement homogeneity, or enhance cement expansion or a combination thereof.

A method for the production of a cavity filled with a low-density mineral foam includes (i) preparing a cement slurry including Portland cement; ultrafine particles of which the D50 is from 10 to 600 nm; a water reducing agent; a manganese salt; and water; wherein the mass ratio of manganese salts/Portland cement is below 0.014; (ii) adding to the cement slurry obtained after (i) a gas-forming liquid including a gas-forming agent; and a viscosity-modifying agent which is a polymer chosen among anionic bio-based polymer, amphiphilic bio-based polymer, alkali swellable acrylic polymer and mixture thereof; to obtain a foaming slurry; (iii) filling the cavity with the foaming slurry obtained at (ii); (iv) leaving the foaming slurry to expand within the cavity.

A method for the production of a cavity filled with a low-density mineral foam includes (i) preparing a cement slurry including Portland cement; ultrafine particles of which the D50 is from 10 to 600 nm; a water reducing agent; a manganese salt; and water; wherein the mass ratio of manganese salts/Portland cement is below 0.014; (ii) adding to the cement slurry obtained after (i) a gas-forming liquid including a gas-forming agent; and a viscosity-modifying agent which is a polymer chosen among anionic bio-based polymer, amphiphilic bio-based polymer, alkali swellable acrylic polymer and mixture thereof; to obtain a foaming slurry; (iii) filling the cavity with the foaming slurry obtained at (ii); (iv) leaving the foaming slurry to expand within the cavity.

A method for the production of a cavity filled with a low-density mineral foam includes (i) preparing a cement slurry including Portland cement; ultrafine particles of which the D50 is from 10 to 600 nm; a water reducing agent; a manganese salt; and water; wherein the mass ratio of manganese salts/Portland cement is below 0.014; (ii) adding to the cement slurry obtained after (i) a gas-forming liquid including a gas-forming agent; and a viscosity-modifying agent which is a polymer chosen among anionic bio-based polymer, amphiphilic bio-based polymer, alkali swellable acrylic polymer and mixture thereof; to obtain a foaming slurry; (iii) filling the cavity with the foaming slurry obtained at (ii); (iv) leaving the foaming slurry to expand within the cavity.

Disclosed herein are low density fiber cement articles, such as fiber cement building panels and sheets, comprised of multiple overlaying fiber cement substrate layers having small and uniform entrained air pockets and low density fillers distributed throughout. The combination of entrained air pockets and low density fillers provide a low density fiber cement matrix with physical and mechanical properties similar to comparable low density fiber cement matrix without entrained air pockets.