This thesis presents a literature review on underground gas storage in rock formations, with a specific focus on CO2 geological storage. The review highlights the intricate interactions between CO2 and reservoir rocks, caprocks, and clay minerals, emphasizing the complexity involved in predicting and optimizing the performance of CO2 storage projects. The impact of CO2 on rock strength and mechanical properties is a key aspect discussed in the review. Studies demonstrate that CO2-brine activity can decrease strength and elastic moduli while enhancing porosity and permeability. However, further research is needed to fully understand the impact of CO2 on rock strength, necessitating comprehensive rock mechanical laboratory testing.