Characterisation of a potential CO2 storage complex and first-order containment risk assessment in the Cambay Basin, India

• The Eocene succession of the Cambay Basin supports several CO 2 storage concepts. • Ankleshwar Formation reservoirs and seals form a potential CO 2 storage complex. • Few seismically resolvable faults affect the potential storage complex. • Legacy wells represent a key containment risk for CO 2 storage in the Cambay Basin. High-level studies have identified potential for subsurface CO 2 storage in India, however lack of detailed technical appraisals aimed at understanding and de-risking the storage resource presents a major challenge to development of CO 2 storage. The onshore Cambay Basin has been identified as a promising target for CO 2 storage given its history of hydrocarbon production and proximity to emission sources. To expedite subsurface characterisation activities in the region, this study uses a 350 km 2 3D seismic volume and well dataset to identify a stratigraphic succession suitable for consideration in a CO 2 storage complex. The Middle to Upper Eocene Ankleshwar Formation comprises several potential reservoir and top seal units which may be considered for storage. A high-level assessment of the stratigraphic and structural characteristics of the Ankleshwar Formation is presented, along with a first-order assessment of the principal containment risks and associated uncertainties. Remaining uncertainties are identified along with suggested appraisal activities to reduce uncertainty and further de-risk the storage concept. Whilst there is considerable uncertainty related to the lateral migration of CO 2 within the storage system, the high number of legacy wells in the study area presents the most significant risk to CO 2 containment.