A Study of Residual Carbon Dioxide Trapping in Sandstone

Abstract

Abstract The storage of carbon dioxide (CO2) in deep brine-filled geologic strata is largely seen as one of the most important tools for CO 2 emissions mitigation on industrial scales. Residual trapping is a major factor in determining the ultimate extent of CO 2 migration within the reservoir. At the same time there are few studies that have observed the trapping characteristics for CO2-brine systems in permeable rocks, including the impact of reservoir conditions, and this remains a major uncertainty for geologic CO 2 storage. In this experimental study, we take advantage of flow conditions that enhance the capillary end effect so that a large saturation gradient across the core is created during drainage with CO2. We observe residual trapping of CO 2 in sandstone rocks across the wide range of conditions representative of subsurface reservoirs suitable for CO 2 storage. The observations are made using a reservoir condition core-flooding laboratory that includes high precision pumps, accurate temperature control, the ability to recirculate fluids for weeks at a time and a rotating X-ray CT scanner. Application of residual trapping curves in reservoir scale simulation has also been discussed.