Perpustakaan Digital ITB

Carbon capture and storage (CCS) in deep saline aquifers represents a vital technological pathway for the mitigation of anthropogenic CO2 emissions, yet the geomechanical integrity of the storage complex remains a primary concern during large-scale operations. This study investigates the potential for fault reactivation within Field-X, a complexly faulted deep saline carbonate aquifer, by employing a two-way coupled flowgeomechanics numerical simulation to evaluate stability, identify critical geomechanical parameters, and determine storage efficiency. To accurately capture the interplay between fluid dynamics and rock deformation, a three-dimensional reservoir model was developed with geomechanical properties distributed using empirical porosity-based correlations, resulting in an average Young’s modulus of 12 GPa and a Poisson’s ratio of 0.32. An injection rate sensitivity analysis established 20 MMSCFD as the optimal operational baseline, producing a peak bottom-hole pressure of 2,863.44 psi safely below the 3,015 psi fracture threshold while sequestering an effective capacity of 7.89 Mt of CO2. To assess the risk of structural failure, a Two-Level Full Factorial Design of Experiments (DOE) was utilized to evaluate eight distinct scenarios, systematically varying fault cohesion (0.1 to 10 MPa), internal friction angles (20° to 40°), and injection rates (20 to 150 MMSCFD). The application of the Mohr-Coulomb failure criterion revealed that fault cohesion is the only statistically significant parameter (t-value > 2.306) governing stability, whereas injection rate and friction angle were statistically insignificant within the tested ranges. This confirms that inherent structural strength is a more critical driver of risk than fluid pressure changes alone. Long-term containment security is supported by three simultaneous trapping mechanisms: Structural Trapping (22.86%), Solubility Trapping (13.12%), and Residual Trapping (64.02%). These results quantify the thresholds where geomechanical properties and operational pressures intersect, establishing a robust framework for defining safe CO2 injection envelopes and highlighting fault cohesion as the priority for site characterization.