The effect of CO2 phase on drainage process by analysis of transient differential pressure

Abstract

CO 2 sequestrated in deep geological formations can be in gaseous, supercritical or liquid state, depending on subsurface pressure and temperature. In this work, CO 2 core flooding experiments are carried to investigate the effect of CO 2 phase on drainage process, especially parameters, such as capillary displacement pressure, relative permeability and displacement efficiency. The results indicate that CO 2 phase significantly affect their breakthrough. The breakthrough took place with the least volume of injected liquid CO 2 (LCO 2), and with the largest volume of gas CO 2 (gCO 2). The capillary displacement pressure can be measured based on the jumps in the pressure profiles, and it shows the largest jump in gCO 2 drainage. The relative permeability is the largest in LCO 2-water displacement and the smallest in gCO 2-water displacement. The displacement efficiency can be improved by increasing capillary number when it is smaller than a critical value around 2×10-8. Keywords: CO 2 phase; CO 2 breakthrough time; capillary displacement pressure; relative permeability; water recovery *Manuscript Click here to view linked References *Declaration of Interest Statement

Parameters Variation and Flow Characteristics when CO2 Displacing Brine in Four Micromodels Simulating Carbon Sequestration in Saline Aquifers

“…5. The differential pressure was consistent with the results of previous study (Jin et al, 2020), and the whole process could be roughly divided into three stages: accumulation stage, breakthrough stage and stabilization stage, as shown in Fig. 5 when the injection rate was 0.1 ml/min.…”

Parameters Variation and Flow Characteristics When CO2 Displacing Brine in Four Micromodels Simulating Carbon Sequestration in Saline Aquifers

“…The differential pressure at the inlet and outlet of the micromodel was recorded by differential pressure gauge during the entire displacement process, as shown in Figure 5. The differential pressure was consistent with the results of previous study, 33 and the whole process could be roughly divided into three stages: accumulation stage, breakthrough stage, and stabilization stage, as shown in Figure 5, when the injection rate was 0.1 mL/min.…”