Methods of cementing include providing a geopolymer cement composition that includes a monophase amorphous hydraulic binder material (MAHBM), a metal silicate, an alkaline activator, and a carrier fluid, introducing the geopolymer cement composition into a subterranean formation, and allowing the geopolymer cement composition to set in the subterranean formation. The MAHBM includes silica or alumina core particulates coated with an amorphous calcium silicate hydrate.

Aqueous polymer dispersions are produced by radically initiated emulsion polymerization of ethylenically unsaturated monomers in the presence of protective colloids and/or emulsifiers in a continuously operated tubular reactor, characterized in that the direction of flow of the reactor contents is reversed along the longitudinal axis of the reactor over the course of polymerization.

The present invention relates to a composition in the form of a mixture comprising F-type fly ash, a reactive silicon source, a setting accelerator and a light aggregate with a density of less than 900 kg/m.sup.3 and a mechanical strength of at least 0.08 MPa, and the uses thereof to obtain light and fireproof construction materials.

The present invention relates to a composition in the form of a mixture comprising F-type fly ash, a reactive silicon source, a setting accelerator and a light aggregate with a density of less than 900 kg/m.sup.3 and a mechanical strength of at least 0.08 MPa, and the uses thereof to obtain light and fireproof construction materials.

Methods of cementing include providing a geopolymer cement composition that includes a monophase amorphous hydraulic binder material (MAHBM), a metal silicate, an alkaline activator, and a carrier fluid, introducing the geopolymer cement composition into a subterranean formation, and allowing the geopolymer cement composition to set in the subterranean formation. The MAHBM includes silica or alumina core particulates coated with an amorphous calcium silicate hydrate.

Methods of cementing include providing a geopolymer cement composition that includes a monophase amorphous hydraulic binder material (MAHBM), a metal silicate, an alkaline activator, and a carrier fluid, introducing the geopolymer cement composition into a subterranean formation, and allowing the geopolymer cement composition to set in the subterranean formation. The MAHBM includes silica or alumina core particulates coated with an amorphous calcium silicate hydrate.

Methods of cementing include providing a geopolymer cement composition that includes a monophase amorphous hydraulic binder material (MAHBM), a metal silicate, an alkaline activator, and a carrier fluid, introducing the geopolymer cement composition into a subterranean formation, and allowing the geopolymer cement composition to set in the subterranean formation. The MAHBM includes silica or alumina core particulates coated with an amorphous calcium silicate hydrate.

A method and agent to induce accelerated creep deformation of shale rock formations in the annular gap between a shale formation and non-cemented sections of a casing string have been developed. A fluid containing alkali silicate or a modified alkali silicate is added to the annular space between the shale rock formation and the casing string. The alkali silicate promotes creep deformation of the shale rock, effectively closing the annulus surrounding the casing. It has been found lithium silicate provides the strongest shale-casing bond and is the presently preferred material for closing abandoned wells.

A method and agent to induce accelerated creep deformation of shale rock formations in the annular gap between a shale formation and non-cemented sections of a casing string have been developed. A fluid containing alkali silicate or a modified alkali silicate is added to the annular space between the shale rock formation and the casing string. The alkali silicate promotes creep deformation of the shale rock, effectively closing the annulus surrounding the casing. It has been found lithium silicate provides the strongest shale-casing bond and is the presently preferred material for closing abandoned wells.

A description is given of the use of an additive mixture (A) for combination with a solution or dispersion (B) comprising waterglass, for producing a moulding material mixture for producing articles from the group consisting of foundry moulds and foundry cores; a multi-component binder system comprising (A) an additive mixture and (B) a solution or dispersion comprising waterglass; a moulding material mixture comprising a mould base material (C) and also components (A) and (B) of such a multi-component binder system; a method for producing an article from the group consisting of foundry moulds and foundry cores; articles from the group consisting of foundry moulds and foundry cores; and the use of such an article for metal casting, preferably for light metal casting, more particularly for aluminium casting.