Volume 53

Surface Gravity Response of CO₂ Storage in the Johansen Deep Saline Aquifer Peizhai Cheng, Pingchuan Dong, Youheng Zhang

Abstract

The storage of CO₂ in geological reservoirs is considered one of the most promising solutions to achieve net zero emissions and address the current climate change crisis by 2050. Based on planning CO₂ storage activities, it is necessary to design accurate on-site characteristics and monitoring during the injection and post injection stages to determine reliable and sustainable geological storage. This study involves the evaluation of surface gravity measurements for monitoring CO₂ plumes in the Johansen deep saline aquifer, which is a potential offshore location for CO₂ geological storage. Use available benchmark models and geological information to simulate injection and post injection stages. The gravity response of the surface was calculated based on the estimation model of reservoir density and saturation at different time intervals and injection rates. Forward calculation is achieved by assuming discretization of tetrahedral grids to ensure accurate and detailed reconstruction of complex reservoirs. The results indicate that the gravity anomaly extends radially around the well site, reaching a peak of approximately -15 μ Gal at an injection rate of 60 kg/s. During the post injection period, the gravity map clearly shows that the saturation of saline water around the injection well increases, and the CO₂ plume migrates towards the shallower part of the reservoir.

Keywords Carbon capture and storage (CCS), CO₂ mass estimation, deep reservoir, gravity monitoring, numerical simulation