Abstract:

 The geological storage of CO₂ is widely accepted as an effective method to reduce the release of greenhouse gases to the atmosphere. Saline aquifer has the most sequestration potential and the most complicated mechanisms among all the sites that could implement CO₂  geological sequestration. Of all the mechanisms, residual gas sequestration has the extremely vital significance in respect of storage capacity and security, and residual gas saturation is a key parameter to calculate the capacity. In this study, an experimental method applied to a rock sample taken from Ordovician reef limestone of Tarim Basin was used to measure the residual gas saturation. Through simulating water flooding supercritical CO₂ saturated core under 40 ℃ strata temperature, 8 MPa strata pressure, the pressure and flux change with time were observed during the course, and  residual gas saturation was measured as 0.368. Before the flooding experiment, sample porosity and permeability coefficient were measured as 2.83% and 5.56×10-9 m/s, respectively, by saturated weighing and permeating experiments.

Key words: residual gas sequestration, residual gas saturation, reef limestone, supercritical CO₂