Application of gravimetric CO monitoring on synthetic data from the Ghawar field, Saudi Arabia.

This study investigates the feasibility of gravimetric monitoring of CO₂ sequestration in the Ghawar field of Saudi Arabia using synthetic modeling based on geological data from Biyadh Sandstone Formation. The reservoir is located at a depth of 900-1000 m, with a formation temperature of approximately 52 °C and formation CO₂ was at a pressure of 10 MPa, resulting in a density of 380 kg/m³. We compute gravity anomalies for various CO₂ plume sizes, considering realistic brine-CO₂ density contrasts and observational noise through the use of a set of type curves. The results show that gravity anomalies in the range of 0.5-1.5 mGal are detectable even for a moderate plume size, and plume thickness can be recovered with an uncertainty of less than 5 m in the presence of 2-4 µGal noise. The significance of this work lies in its contribution to global efforts to mitigate climate change through secure and verifiable CO₂ storage. Gravimetry offers a cost-effective, non-invasive monitoring solution that remains sensitive to the total injected mass of CO₂ regardless of its internal distribution. The proposed workflow is adaptable for real-time assessment and long-term verification of CO₂ storage performance in deep saline formations.