Integrated numerical simulation and source‐sink matching methodology for Basin‐Wide CO ₂ storage assessment in depleted reservoirs: A Cambay Basin case study

Abstract

India needs to focus on permanent CO ₂ storage in the depleted hydrocarbon reservoirs to meet the net‐zero emission goals. This study evaluates the CO ₂ storage capacity of mature fields within the Cambay Basin using the case of the Gandhar‐Hazad reservoir. A composite method that involves source‐sink matching, production depletion history matching, and compositional reservoir simulation is used. Significant CO ₂ ‐emitting industries in Gujarat are filtered and equated with appropriate sinks to reduce the transportation distance and enhance the viability of the project. Field‐specific petrophysical properties and data on reservoir pressure are used to construct a three‐dimensional geological model. The General Equation‐of‐state model Multicomponent (GEM) reservoir simulator (from Computer Modeling Group, CMG‐GEM) is used to simulate continuous and water‐alternating‐gas (WAG) CO ₂ injection under geomechanical and capillary constraints, explicitly incorporating hysteresis, CO ₂ ‐brine solubility, and long‐term trapping mechanisms. The findings suggest that WAG injection offers high sweep efficiency and plume migration. It increases residual and solubility trapping processes. The percentage of CO ₂ immobilized is around 45%–55% during the simulation period. The first water saturation, porosity, and injection parameters are found to be the most influential trapping performance controls when using CMOST‐AI optimization and Morris sensitivity analysis. The suggested workflow decreases geological and operational uncertainty. It shows that the scalable storage of CO ₂ in the intricate mature Cambay Basin reservoirs is technically feasible.