Gaseous CO2 behaviour during water displacement in a sandstone core sample

Abstract

CO2 injection into subsurface formations involves the flow of CO2 through a porous medium that also contains water. The injection, displacement, migration, storage capacity and security of CO2 is controlled mainly by the interfacial interactions and capillary, viscous, and buoyancy forces which are directly influenced by changes in subsurface conditions of pressure and temperature; the impact of bouncy forces is assumed negligible during this study. In this study, gaseous CO2 is injected into a water-saturated sandstone core sample to explore the impact of fluid pressure (40-70 bar), temperature (29-45 °C), and CO2 injection rate (0.1-2 ml/min) on the dynamic pressure evolution and displacement efficiency. This study highlights the impact of capillary or viscous forces on the two-phase flow characteristics and shows the conditions where capillary or viscous forces become more influential. The results reveal a moderate to considerable impact of the parameters investigated on the differential pressure profile, endpoint CO2 relative permeability (KrCO2 max), and irreducible water saturation (Swr). Overall, the increase in fluid pressure, temperature, and CO2 injection rate cause an increase in the maximum and final differential pressures, an increase in the KrCO2 max , a reduction in the Swr. Swr was in the range of around 0.38-0.45 while KrCO2 max was less than 0.25. The data show a significant influence for the capillary forces on the pressure and production behaviour. The capillary forces produce high oscillations in the pressure and production data while the increase in viscous forces impedes the appearance of these oscillations. The appearance and frequency of the oscillations depend on the fluid pressure, temperature, and CO2 injection rate but to different extents.

Characterizing Tracer Transport Behavior in Two‐Phase Flow System: Implications for CO2 Geosequestration

“…The change in CO 2 saturation also caused a decrease in averaged ∆P . Although a significant variation in ∆P was observed due to capillary and viscous forces (Al‐Zaidi et al, 2019) during the four tracer release tests, the overall averaged ∆P decreased from 7.69 to 5.95 kPa. A more detailed discussion is given in section 3.2.…”

Research on Displacement Diffusion Model of Time-Varying Slurry with Rheological Parameters in Unsaturated Media

“…The application of displacement model in the field of oil and gas development has been relatively mature, such as oil and gas production technology of water pressure drive oil. Different from the obvious interface between oil and gas two immiscible fluids in petroleum exploitation engineering [25][26][27]. When the slurry in the water-bearing stratum of unsaturated soil is displacing and diffusing, there is a certain miscibility between slurry and pore fluid, so a thin miscible transition zone is formed.…”

“…Substituting Equation (26) into Equation ( 25), the power-law slurry infiltration diffusion equation is given as follows:…”