The composition for preparation of a fire resistant interlayer includes an aqueous alkali silicate solution and a silicon dioxide compound. The composition has a molar ratio of silicon dioxide (SiO2) to alkali metal oxide (M2O) of larger than 2. The composition further includes a stabilisation agent and the stabilisation agent includes zinc (Zn).

The composition for preparation of a fire resistant interlayer includes an aqueous alkali silicate solution and a silicon dioxide compound. The composition has a molar ratio of silicon dioxide (SiO2) to alkali metal oxide (M2O) of larger than 2. The composition further includes a stabilisation agent and the stabilisation agent includes zinc (Zn).

A cement composition for use in a well that penetrates a subterranean formation comprising: cement; water; and an additive comprising zirconium dioxide, wherein at least a portion of the zirconium dioxide is in a metastable tetragonal phase, and wherein some or all of the zirconium dioxide that is in the metastable tetragonal phase transforms to a stable monoclinic phase after a stress is applied to the cement composition. The additive also reduces the dimensions of a crack located within the set cement composition. A method of cementing in a subterranean formation comprising: introducing a cement composition into the subterranean formation.

A cement composition for use in a well that penetrates a subterranean formation comprising: cement; water; and an additive comprising zirconium dioxide, wherein at least a portion of the zirconium dioxide is in a metastable tetragonal phase, and wherein some or all of the zirconium dioxide that is in the metastable tetragonal phase transforms to a stable monoclinic phase after a stress is applied to the cement composition. The additive also reduces the dimensions of a crack located within the set cement composition. A method of cementing in a subterranean formation comprising: introducing a cement composition into the subterranean formation.

The present invention relates to a method to reduce the water loss in slurries and solutions used in oil field or gas field operations, for example for drilling, cementing and completion operations by adding a copolymer having a high molecular weight characterized by a K value of at least 300, said copolymer comprising structural units derived from monomers having sulfonic acid or derivative thereof, phosphonic acid or derivative thereof and acrylamide functionality.

The present invention relates to a method to reduce the water loss in slurries and solutions used in oil field or gas field operations, for example for drilling, cementing and completion operations by adding a copolymer having a high molecular weight characterized by a K value of at least 300, said copolymer comprising structural units derived from monomers having sulfonic acid or derivative thereof, phosphonic acid or derivative thereof and acrylamide functionality.

The invention describes a phosphate-based inorganic binder obtained by reaction between at least one basic constituent and an acidic phosphate salt, in the presence of a retarder which is an X.sup.+A.sup. salt, the solubility of which in an aqueous medium, measured at 25 C., is greater than that of the acidic phosphate salt, and in which: X.sup.+ is a cation chosen from alkali metals, alkaline earth metals, zinc, aluminium and the ammonium ion, and A.sup. is an acetate, formate, benzoate, tartrate, oleate, oxalate, bromide or iodide anion.

The invention describes a phosphate-based inorganic binder obtained by reaction between at least one basic constituent and an acidic phosphate salt, in the presence of a retarder which is an X.sup.+A.sup. salt, the solubility of which in an aqueous medium, measured at 25 C., is greater than that of the acidic phosphate salt, and in which: X.sup.+ is a cation chosen from alkali metals, alkaline earth metals, zinc, aluminium and the ammonium ion, and A.sup. is an acetate, formate, benzoate, tartrate, oleate, oxalate, bromide or iodide anion.

Bismuth oxyhalide-added building materials are disclosed. The building material is a binder-containing building material, which sets and harden when mixed with water, such as gypsum and cement-based building material. Methods for applying bismuth oxyhalidecomprising coatings onto surfaces of building materials, to protect them against pollutants, are described.

Bismuth oxyhalide-added building materials are disclosed. The building material is a binder-containing building material, which sets and harden when mixed with water, such as gypsum and cement-based building material. Methods for applying bismuth oxyhalidecomprising coatings onto surfaces of building materials, to protect them against pollutants, are described.