CO2 storage in depleted oil and gas reservoirs: A review

Geological storage of CO2 in depleted oil and gas reservoirs is approved due to its advantages, such as strong storage capacity, good sealing performance, and complete infrastructure. This review clarified the existing projects, advantages, significances, influencing factors, mechanisms, and storage potential evaluation procedures of CO2 storage in depleted oil and gas reservoirs. In this review, the storage capability of depleted oil and gas reservoirs has been confirmed, and factors affecting the CO2 storage potential, including geological factors and engineering factors, are concluded. CO2 trapping mechanisms of different storage processes in depleted oil and gas reservoirs are elaborated and divided into three stages. The evaluation stages of CO2 storage potential of depleted oil and gas reservoirs are summarized as basin selection evaluation stage, oil and gas reservoir selection evaluation stage, storage security evaluation using the bowtie method, and storage capacity calculation stage. The calculation accuracy of CO2 storage capacity in depleted oil and gas reservoirs can be optimized by determining the mineralization storage volume and the actual reservoir characteristics of the dissolution storage coefficient numerically. This work intends to provide support for the storage of CO2 by analyzing and studying the geological theory and engineering achievements of CO2 storage in depleted oil and gas reservoirs.