Abstract
Carbon capture, utilization, and storage (CCUS) technologies have become critical tools in mitigating anthropogenic greenhouse gas emissions and achieving global climate targets. This study investigates the potential for CO₂ sequestration in the depleted gas reservoirs of the Tengiz field, a unique site characterized by deep reservoir conditions and a history of extensive hydrocarbon extraction. The research aims to evaluate the technical feasibility and effectiveness of CO₂ injection into a high-temperature, high-pressure formation, using dynamic reservoir simulation. Key objectives include assessing injection capacity, breakthrough time, storage efficiency, and pressure behavior under varying operational scenarios. The study integrates geological, petrophysical, and fluid data to build a robust sector model, calibrated with historical production data. Simulation results demonstrate favorable injectivity and containment, with minimal risk of CO₂ leakage. These findings contribute to the growing body of knowledge on field-scale CCUS deployment and support the development of sustainable carbon management strategies in mature oil and gas provinces.