ANALYSIS OF EXPANDING CEMENT USING LATEX AND MICROSILICA ADDITIVES FOR GAS ISOLATION IN CO₂ STORAGE WELLS

Abstract

Gas migration in CO₂ storage wells poses a critical risk to well integrity and long-term containment. This study evaluates the effect of combining microsilica and latex as an alternative mechanical-expansion cement system to mitigate gas migration without the use of chemical expanding agents. Four cement slurry formulations were tested: base cement (Base), cement with microsilica (MS), cement with latex (LX), and a combination of microsilica and latex (MS + LX). Laboratory tests included rheology, thickening time, com-pressive strength, fluid loss, and expansion ring tests. The results demonstrated that Sample MS + LX delivered the most optimal performance, exhibiting great rheological performance, a clear right angle set behavior, and the greatest volumetric expansion (0.454%) over 7 days. Microsilica accelerated early hydration and refined pore structure, while latex introduced elasticity that enabled controlled expansion. Their combination produced stable mechanical expansion capable of sealing microannuli and reducing the risk of gas invasion. Although this study did not simulate CO₂ exposure, the findings indicate that the microsilica–latex system is a promising alternative for expanding cement design in CO₂ storage wells. This provides a strong foundation for further development of non-chemical expanding cement systems to support safe and sustainable carbon capture and storage (CCS) operations.