Study On Gas/Liquid Flow Characteristic In Porous Media During CO₂Geological Storage

CO2has drawn a worldwide attention due to greenhouse effect. One of the most promising concepts is Carbon dioxide capture and storage in saline aquifers, which are estimated to have great capacity. The key problems during CO2storage in saline aquifers process focus on the pore structure, heat transfer and transport properties, the coupling interaction of porous media and fluids, the security of the storage and so on. So the study on multiphase flow properties in porous media at laboratory scale is important to mechanisms of CO2storage in saline aquifers. In the paper, some research have been studied using MRI and X-ray CT technique:the structure of the porous media, pipe flow and flow in porous media, displacement process in porous media and relative permeability curves, also the temperature distribution in water and water saturated porous media was investigated. The study provides useful data regarding the reservoir optimization, injection mode and the transport processes in the geological storage of CO2.The magnetic resonance imaging(MRI) experimental set up was included three parts: MRI system,CO2and water injection system and recycling system. The average porosity along the porous media and radial porosity distribution can be determined. Then the fractal dimension were calculated from the pore structure. The absolute permeability were calculated from the simple K-C model and modified K-C model. Also X-ray CT experimental setup was built and the average porosity was also investigated. Even three dimension heterogeneity porosity and permeability distribution were obtained.The temperature distribution in water and water saturated porous media were investigated. A temperature sensitive MRI parameter(ri) was evaluated to measure temperature distribution induced heating and cooling in water and water saturated porous media sample. The SPRG and SEMS sequences were used for Ti method.With a modified spin echo sequence, the single phase flow properties in pipe and porous media were investigated. The two dimension and three dimension velocity distribution with different flow rates were obtained. The results showed the heterogeneous distribution of velocity, and the distribution also means heterogeneous distribution of pore. The relationship between the velocity and pore distribution was investigated. Also flow paths phenomena in porous media were found. Three orthogonal components velocity (Vx, Vy and Vz) of single phase flow measurement were carried out. The reversed flow was described from the radial velocity distribution and vector diagram. Based on the velocity distribution, the permeability was obtained. The gas and supercritical CO2displacement processes in porous media were investigated. The two phase fluids flow properties in porous media were investigated. The factor of injection flow rate, temperature and pressure on the displacement processes were analyzed. The two phase saturation during the displacement processes were obtained. The CO2channeling or fingering phenomena was obviously for the difference of permeability. The two phase velocity during the displacement processes were also obtained The relationship between the capillary number and displace process and residual saturation were discussed.The relative permeability curves are calculated using a unsteady state, Brooks-Corey model and a steady method. The coupling interaction of porous media and fluids were analyzed. The relative permeability is a decreasing function of the capillary number. The preliminary study on initial CO2saturation and residual saturation was carried out.