The present disclosure provides methods, compositions, and systems embodying cement compositions and the synergistic effect of lost circulation materials (LCMs) and fluid loss control additives (FLCAs) thereupon for cementing subterranean zones. A method of subterranean well cementing, comprising providing a cement composition comprising a hydraulic cement, a first FLCA, an LCM, and water, wherein the first FLCA comprises a water-soluble polymer with repeating units comprising a 5- to 6-membered cyclic amide; introducing the cement composition into a wellbore penetrating a subterranean formation, wherein inclusion of the first FLCA and the LCM in the cement composition fluid reduces fluid loss into the subterranean formation, wherein the subterranean formation has fractures with a width of from about 1 micron to about 800 microns, and wherein the subterranean formation has a permeability of about 1 milliDarcy to about 300 Darcy; and allowing the cement composition to set in the subterranean formation.

The present disclosure provides methods, compositions, and systems embodying cement compositions and the synergistic effect of lost circulation materials (LCMs) and fluid loss control additives (FLCAs) thereupon for cementing subterranean zones. A method of subterranean well cementing, comprising providing a cement composition comprising a hydraulic cement, a first FLCA, an LCM, and water, wherein the first FLCA comprises a water-soluble polymer with repeating units comprising a 5- to 6-membered cyclic amide; introducing the cement composition into a wellbore penetrating a subterranean formation, wherein inclusion of the first FLCA and the LCM in the cement composition fluid reduces fluid loss into the subterranean formation, wherein the subterranean formation has fractures with a width of from about 1 micron to about 800 microns, and wherein the subterranean formation has a permeability of about 1 milliDarcy to about 300 Darcy; and allowing the cement composition to set in the subterranean formation.

Drilling fluid compositions and methods of using them are described. The drilling fluid compositions comprise nanocomposites comprising core-shell morphology, wherein the core material comprises a nanoparticle having an average particle size of about 5 nm to 100 nm, and the shell material comprises a crosslinked polymer comprising acrylamide repeat units. The nanocomposites are effective fluid loss control agents when the drilling fluids are employed in mud drilling operations.

The invention relates to a composition for a powder mortar comprising one or more fillers, one or more binders, one or more thickeners and optionally further additives, wherein at least one of the one or more binders comprises a starch, and wherein at least one of the one or more thickeners is an etherified starch. The invention further relates to a corresponding powder mortar, in particular for use as a spackling compound.

The invention relates to a composition for a powder mortar comprising one or more fillers, one or more binders, one or more thickeners and optionally further additives, wherein at least one of the one or more binders comprises a starch, and wherein at least one of the one or more thickeners is an etherified starch. The invention further relates to a corresponding powder mortar, in particular for use as a spackling compound.

An additive for oil well cement contains a vinyl alcohol polymer and has good fluid loss reducing performance. The additive for oil well cement is a saponified product of a copolymer of a vinyl ester monomer and a multifunctional monomer, and has a degree of saponification of 70 to 95 mol % and a viscosity-average degree of polymerization of 1000 to 10000.

A lost circulation material (LCM) composition for sealing lost circulation zones in wellbores may include 50 weight percent to 97 weight percent epoxy resin, 2 weight percent to 30 weight percent curing agent, 0.1 weight percent to 40 weight percent weighting material, and 0.1 weight percent to 20 weight percent amide accelerator. The LCM composition may have a density of greater than or equal to 1121 kilograms per cubic meter and may be capable of being injected through a drill bit of a drill string into the lost circulation zone. The amide accelerator may enable the viscosity of the LCM composition to be reduced while providing a reduced cure time. Methods of treating a lost circulation of a wellbore with the LCM compositions are also disclosed.

A lost circulation material (LCM) composition for sealing lost circulation zones in wellbores may include 50 weight percent to 97 weight percent epoxy resin, 2 weight percent to 30 weight percent curing agent, 0.1 weight percent to 40 weight percent weighting material, and 0.1 weight percent to 20 weight percent amide accelerator. The LCM composition may have a density of greater than or equal to 1121 kilograms per cubic meter and may be capable of being injected through a drill bit of a drill string into the lost circulation zone. The amide accelerator may enable the viscosity of the LCM composition to be reduced while providing a reduced cure time. Methods of treating a lost circulation of a wellbore with the LCM compositions are also disclosed.

Provided is a vinyl alcohol polymer having good fluid loss reducing performance. The vinyl alcohol polymer is a saponified product of a copolymer of a vinyl ester monomer and a multifunctional monomer, and has a degree of saponification of 70 to 95 mol % and a viscosity-average degree of polymerization of 1000 to 10000.

An anti-radiation concrete comprising a geopolymer is described. In an implementation, the anti-radiation concrete comprises a mixture of at least two aqueous alkaline activators, fine aggregate, and coarse aggregate from high density metal-containing rocks.