Convection and Diffusion of Supercritical Carbon Dioxide in High-Pressure Porous Media Filled with Water

本文对封闭条件下超临界CO_2和水在多孔介质中的两相流动进行了实验和数值研究。我们使用磁共振成像技术直接显示了超临界二氧化碳注入含水多孔介质中的分布。在模拟700~1000m深度含水层的条件下，成功地显示了贝里亚砂岩岩心和玻璃微珠填充层中的原位含水饱和度分布。通过将Coreflood解释方法应用于我们的饱和度数据，我们可以将局部Darcy相速度描述为饱和度的函数。最后，通过对比模拟1000m和700m含水层的两种情况下的数据，讨论了浮力对驱替过程和重力主导的纯逆流流动的影响，发现浮力在很大程度上控制了…的纯逆流流动渗透性更好的多孔介质，适用于700米和1000米深的条件。用格子Boltzmann方法模拟了超临界CO2和水在多孔介质中的两相流动，包括界面张力、润湿性、浮力和粘度比的影响。目前的研究表明，润湿性和界面张力影响相对渗透率偏离达西定律在较低的体力，如浮力。因此，应考虑润湿性和界面张力对相对渗透率的影响，以便通过大头皮油藏模拟来估计封存CO2的长期去向。CO2的相对渗透率随着水的毛细压力的增加而减小，毛细压力会使CO2的流动速度比以往的模拟结果要慢。由于毛管压力在盖层中的影响很大，因此偏离达西定律对CO2在盖层中的泄漏是至关重要的。较少

This paper describes experimental and numerical research on two-phase flow of supercritical CO_2 and water in porous media under sequestration conditions. We used a magnetic resonance imaging technique to directly visualize the distribution of supereritical CO_2 injected into porous media containing water. in situ water saturation distributions in a Berea sandstone core and a packed bed of glass beads were successfully visualized under conditions that simulate those at 700 -1000-m depths in an aquifers at the depth in the range from 700m to 1000m. By applying the coreflood interpretation method to our saturation data, we could describe the local Darcy phase velocities as a function of saturation. Finally, the effect of buoyancy on displacement process and gravity dominated pure counter-current flow is discussed by comparing the data obtained at two conditions that model the aquifers at depths of 1000 m and 700 m. We found that buoyancy largely controls the pure counter-current flow in … More well permeable porous media for conditions at 700 and 1000-m depths. We had developed a numerical code, which simulates two-phase flow of supercritical C0_2 and water in porous media including the effect of interfacial tension, wettability, buoyancy, and viscosity ratio, by a lattice Boltzmann method. A present study shows that the wettability and interfacial tension affect the relative permeability to deviate from Darcy law at low body forces such as buoyancy. Therefore, the effect of wettability and interfacial tension on the relative permeability should be taken into account to estimate the long-term fate of sequestered C0_2 by large-scalp reservoir simulations. The relative permeability of C0_2 decreases with an increase of the capillary pressure of water, As a result, the capillary pressure could make the flow of C0_2 slower than that has estimated in former simulations. Since the effect of the capillary pressure is significant in cap-rocks, the deviation from Darcy law is vital to the leakage of C0_2 through the cap-rocks. Less