Abstract: Cement retarders are based on blends of lignosulfonate compounds, borate compounds and gluconate compounds. The compounds are present in certain ratios that allow the retarders to operate at temperatures and pressures up to and exceeding about 176° C. and 152 MPa. The retarders may also be provided in liquid form, improving their suitability for use at offshore well-site locations.

Abstract: Cement retarders are based on blends of lignosulfonate compounds, borate compounds and gluconate compounds. The compounds are present in certain ratios that allow the retarders to operate at temperatures and pressures up to and exceeding about 176° C. and 152 MPa. The retarders may also be provided in liquid form, improving their suitability for use at offshore well-site locations.

Abstract: Spacer fluids that are stable at temperatures up to at least 260° C. comprise water, polystyrene sulfonate and a mixture of particulate materials. The particulate materials may be chosen such that the mixture has at least a trimodal particle-size distribution. The fluids may further comprise inorganic clays, mutual solvents and surfactants.

Abstract: Well-cementing compositions for use in high-pressure, high-temperature (HPHT) wells are often densified, and contain weighting agents such as hematite, ilmenite, barite and hausmannite. The weighting agents are usually finely divided to help keep them suspended in the cement slurry. At high temperatures, finely divided weighting agents based on metal oxides react with the calcium-silicate-hydrate binder in set Portland, cement, leading to cement deterioration. Finely divided weighting agents based on metal sulfates are inert with respect to calcium silicate hydrate; consequently, set-cement stability is preserved.

Abstract: Well-cementing compositions for use in high-pressure, high-temperature (HPHT) wells are often densified, and contain weighting agents such as hematite, ilmenite, barite and hausmannite. The weighting agents are usually finely divided to help keep them suspended in the cement slurry. At high temperatures, finely divided weighting agents based on metal oxides react with the calcium-silicate-hydrate binder in set Portland cement, leading to cement deterioration. Finely divided weighting agents based on metal sulfates are inert with respect to calcium silicate hydrate; consequently, set-cement stability is preserved.

Abstract: Spacer fluids that are stable at temperatures up to at least 300° C. comprise water, polystyrene sulfonate and a mixture of particulate materials. The particulate materials may be chosen such that the mixture has at least a trimodal particle-size distribution. The fluids may further comprise inorganic clays, mutual solvents and surfactants.

Abstract: Spacer fluids that are stable at temperatures up to at least 260° C. comprise water, polystyrene sulfonate and a mixture of particulate materials. The particulate materials may be chosen such that the mixture has at least a trimodal particle-size distribution. The fluids may further comprise inorganic clays, mutual solvents and surfactants.

Abstract: High-specific-gravity micronized particulates, added to cement slurries in conjunction with certain high-molecular-weight water-soluble polymers, improve fluid-loss control of cement slurries during placement in subterranean wells. The particulates may have a specific gravity higher than 3, and a median particle size smaller than 3 ?m. The particulates may include barite, manganese tetraoxide, titanium oxide, iron titanium oxide and aluminum oxide.

Abstract: Cement retarders are based on blends of lignosulfonate compounds, borate compounds and gluconate compounds. The compounds are present in certain ratios that allow the retarders to operate at temperatures and pressures up to and exceeding about 176° C. and 152 MPa. The retarders may also be provided in liquid form, improving their suitability for use at offshore well-site locations.

Abstract: Well-cementing compositions for use in high-pressure, high-temperature (HPHT) wells are often densified, and contain weighting agents such as hematite, ilmenite, barite and hausmannite. The weighting agents are usually finely divided to help keep them suspended in the cement slurry. At high temperatures, finely divided weighting agents based on metal oxides react with the calcium-silicate-hydrate binder in set Portland, cement, leading to cement deterioration. Finely divided weighting agents based on metal sulfates are inert with respect to calcium silicate hydrate; consequently, set-cement stability is preserved.

Abstract: Well-cementing compositions for use in high-pressure, high-temperature (HPHT) wells are often densified, and contain weighting agents such as hematite, ilmenite, barite and hausmannite. The weighting agents are usually finely divided to help keep them suspended in the cement slurry. At high temperatures, finely divided weighting agents based on metal oxides react with the calcium-silicate-hydrate binder in set Portland cement, leading to cement deterioration. Finely divided weighting agents based on metal sulfates are inert with respect to calcium silicate hydrate; consequently, set-cement stability is preserved.