Balancing Capacity and Containment: A Technical Evaluation of CO2 Storage in Saline and Depleted Reservoirs of the Talpha Field

Abstract This study looks at the concept of CO2 storage from a Geoscience-based approach through geological storage evaluation and comparative analysis of caprocks in the Talpha field. Through the integration of geoscience workflows- petrophysical analysis, seismic interpretation, static modelling with data analysis, two reservoirs are evaluated for their carbon storage potentials. Reservoir A is a saline reservoir that demonstrated higher computed storage capacity of 5.10 million cubic meters (3.06 million metric tonnes) due to its relatively higher average porosity of 25% and net-to-gross ratio of 80%. Reservoir E, a depleted hydrocarbon reservoir, however showed a lower computed storage capacity of 2.18 million cubic meters (1.31 million metric tonnes) due to its relatively lower average porosity and thickness. In addition to the petrophysical evaluation, seismic data was interpreted and a 100×100 static model was built to capture the structural and stratigraphic attributes of the field. Several model quality checks such as bulk volume, cell angle, and cell inside-out were carried out. Absence of core data and geomechanical data which validates reservoir properties and variability is a significant limitation of this study, highlighting the importance of these datasets for future studies. By evaluating storage capacity and containment security, this research highlights the critical role of geoscience in guiding CCS site selection and management, thereby contributing to global carbon emissions reduction efforts.