Perpustakaan Digital ITB

Carbon Capture and Storage (CCS) in deep saline aquifers is a key climate mitigation strategy, though large-scale CO2 injection is constrained by reservoir pressure buildup that can compromise storage integrity. This study evaluates structural, residual, and solubility trapping performance over a 20-year injection period, employing brine production wells to relieve this pressure. The solubility trapping model, integrating all three mechanisms, serves as the basis for a sensitivity analysis on parameters governing trapped and dissolved CO2. A 3D compositional reservoir model was simulated in CMG-GEM under a five-spot configuration consisting of four CO2 injection wells and one brine production well. Each trapping mechanism was simulated individually and progressively integrated to assess its contribution to total CO2 storage. The validated solubility trapping model was then evaluated against six reservoir parameters (permeability, porosity, depth, pressure, temperature, salinity) and five operational parameters (well spacing, injection rate, brine production rate, maximum bottom-hole pressure, allowable CO2 breakthrough) using CMG-CMOST. Polynomial regression was applied to construct proxy models predicting the amount of trapped and dissolved CO2. Simulation results show that solubility trapping sequesters the highest proportion of CO2 at 84.6%, followed by residual trapping at 10,5%, confirming the dominance of dissolution-driven storage in deep saline aquifer conditions under active pressure management. The proxy model for trapped CO2 achieved an R-squared of 0.702 (training) and 0.833 (validation), with well spacing, permeability, and injection rate identified as the most significant parameters. The proxy model for dissolved CO2 achieved an R-squared of 0.877 (training) and 0.797 (validation), primarily governed by brine salinity, injection rate, and reservoir top depth. These results indicate that operational parameters, particularly those related to well placement and injection design, exert a stronger influence on short-term CO2 trapping and dissolution performance than static reservoir properties. This study presents an integrated framework that couples multiple trapping mechanisms with active pressure management and proxy modeling, providing a computationally efficient tool for predicting CO2 sequestration performance and optimizing injection-production well design in pressure-constrained saline aquifer storage projects.