Abstract: The Portland cement type-G with nanosilica additive for high pressure-high temperature applications is a mixture of about 1.0%-2.0% by dry weight of nanoparticles of hydrophilic silica, with type-G Portland cement (and other admixtures) forming the balance of the mixture. The cement so formed is suitable for use in deep petroleum wells, which require cement that can be introduced under high temperature (about 290° F.) and high pressure (about 8,000-9,000 PSI) conditions. The addition of hydrophilic nanosilica shortens the thickening time for the cement slurry and causes a growth in the average compressive strength of the cement. In addition, the hydrophilic nanosilica does not cause any free water separation from the cement slurry column after aging.

Abstract: The Portland Saudi cement type-G with nanosilica additive for high pressure-high temperature applications comprises a mixture of about 1.0%-2.0% by dry weight of nanoparticles of silica; and type-G Portland Saudi cement forming the balance of the mixture. The cement so formed is suitable for use in deep petroleum wells, which require cement that can be introduced under high temperature (about 290° F.) and high pressure (about 8,000-9,000 psi) conditions. The addition of nanosilica shortened the thickening time for the cement slurry and caused a growth in the average compressive strength of the cement samples. In addition, the nanosilica did not cause any free water separation from the cement slurry column after aging.