Improvement of the resistance to carbon dioxide corrosion of oil well cement by micron diabase powder in high-temperature environment

In response to the challenge of carbon dioxide (CO2) corrosion of oil well cement in high-temperature environments, the effect of micron diabase powder on the resistance of oil well cement to corrosion was studied. By simulating the simultaneous presence of high-temperature and CO2, the effect of adding micron diabase powder on the corrosion resistance of oil well cement was evaluated, and the mechanism by which oil well cement was affected was analyzed. The results showed that the addition of micron diabase powder significantly improved the compressive strength of oil well cement while reducing the permeability and corrosion degree of the samples. After 21 days of corrosion under 120 degrees C and 30 MPa (CO2 partial pressure of 21 MPa), the compressive strength of cement containing 15 wt% diabase powder (Z3) increased by 53.93 %, and the permeability decreased by 58.84 % compared to the blank sample (Z0), while the corrosion degree of cement sample is 15.09 %. The addition of micron diabase powder promotes the formation of tobermorite after hydration of oil well cement at high temperatures, reducing the content of alpha-dicalcium silicate hydrate (alpha-C2SH). At the same time, the main components in micron diabase powder make the structure of oil well cement denser after hydration, thus exhibiting higher resistance to CO2 corrosion in high-temperature acidic gas environments. This study provides a new perspective for the development of cementing materials to improve the corrosion resistance of oil well cement.