A method for making a low cost, lightweight carbon aggregate from coal at, above, or below atmospheric pressure, and a lightweight concrete composition utilizing the lightweight carbon aggregate is described.

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 CO.sub.2 and/or brine. The resulting concretes are suitable cementing material for oil and gas wells as well as wellbores for geologic carbon sequestration.

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 CO.sub.2 and/or brine. The resulting concretes are suitable cementing material for oil and gas wells as well as wellbores for geologic carbon sequestration.

Aqueous compositions may be used preparing special concretes like aerated concrete or lightweight concrete. Such an aqueous composition for preparing such concretes, may combine water, a hydraulic binder, and an aggregate that is ground in the presence of a particular anionic polymer. The ground aggregate is selected from slag, fly ash, sand, and combinations thereof.

Aqueous compositions may be used preparing special concretes like aerated concrete or lightweight concrete. Such an aqueous composition for preparing such concretes, may combine water, a hydraulic binder, and an aggregate that is ground in the presence of a particular anionic polymer. The ground aggregate is selected from slag, fly ash, sand, and combinations thereof.

The effectiveness of expansive cement systems may be diluted when, during a well cementing operation, commingling takes place between the cement slurry and a spacer fluid, a drilling fluid, or both. Incorporating expansive agents in the spacer fluid or drilling fluid may reduce or negate the loss of expansion at the cement slurry/spacer interface or the cement slurry/drilling fluid interface, thereby promoting zonal isolation throughout the cemented interval.

The effectiveness of expansive cement systems may be diluted when, during a well cementing operation, commingling takes place between the cement slurry and a spacer fluid, a drilling fluid, or both. Incorporating expansive agents in the spacer fluid or drilling fluid may reduce or negate the loss of expansion at the cement slurry/spacer interface or the cement slurry/drilling fluid interface, thereby promoting zonal isolation throughout the cemented interval.

Methods and compositions are provided that relate to cementing operations. Methods and compositions that include pumice in geopolymer cement compositions comprising slag.

Methods and compositions are provided that relate to cementing operations. Methods and compositions that include pumice in geopolymer cement compositions comprising slag.

The present invention provides a composition for forming a lightweight, low shrinkage and hydrophobic cementitious matrix, and a method for preparing thereof. The present cementitious matrix formed by the composition is lightweight, hydrophobic (or water repelling) and with low shrinkage which is useful in building and construction industry as non-structural wall resistant to water, heat and sound entry. The present invention also provides a method of preparing the composition and the cementitious matrix formed from the composition.