Abstract: Cement compositions containing a hydraulic cement, a synthetic phyllosilicate (e.g. Laponite®), and silica flour. The cement compositions may optionally include other additives such as an expandable agent, a defoamer, and a fluid loss controller. Cement slurries and wellbore cements made therefrom are also specified. The inclusion of the synthetic phyllosilicate has enhanced the mechanical strength, improved the density homogeneity, as well as decreased the permeability of the wellbore cement, making it suitable for cementing oil and gas wells under high pressure and high temperature (HPHT) conditions.

Abstract: Cementing compositions containing a hydraulic cement, halloysite nanoparticles, and silica flour. The cementing compositions may optionally include other additives such as a friction reducer, a defoamer, and a fluid loss additive. Cement samples made therefrom and methods of producing such cement samples are also specified. The addition of halloysite nanoparticles and silica flour provides enhanced mechanical strength (e.g. compressive strength, flexural strength) and improved durability (e.g. resistance to CO2 and salinity) to the cement, making them suitable cementing material for oil and gas wells.

Abstract: A carbonation-resistant cementitious blend containing cement, an expandable agent present, a dispersion agent, a fluid loss additive, a defoamer, and an olive waste. Concrete samples made therefrom and methods of producing such concrete samples are also specified. The addition of olive waste provides enhanced durability (carbonation resistance) and maintains mechanical strength (e.g. compressive strength, tensile strength) after exposure to CO2 and/or brine. The resulting concretes are suitable cementing material for oil and gas wells as well as wellbores for geologic carbon sequestration.

Abstract: Cementing compositions containing a hydraulic cement, halloysite nanoparticles, and silica flour. The cementing compositions may optionally include other additives such as a friction reducer, a defoamer, and a fluid loss additive. Cement samples made therefrom and methods of producing such cement samples are also specified. The addition of halloysite nanoparticles and silica flour provides enhanced mechanical strength (e.g. compressive strength, flexural strength) and improved durability (e.g. resistance to CO2 and salinity) to the cement, making them suitable cementing material for oil and gas wells.

Abstract: Cement compositions containing a hydraulic cement, a synthetic phyllosilicate (e.g. Laponite®), and silica flour. The cement compositions may optionally include other additives such as an expandable agent, a defoamer, and a fluid loss controller. Cement slurries and wellbore cements made therefrom are also specified. The inclusion of the synthetic phyllosilicate has enhanced the mechanical strength, improved the density homogeneity, as well as decreased the permeability of the wellbore cement, making it suitable for cementing oil and gas wells under high pressure and high temperature (HPHT) conditions.