抄録
Residual gas trapping by capillarity is considered to be an important trapping mechanism in CO_2 geological storage. In this paper, gas trapping in porous media of vertical and horizontal sandstone cores is investigated from a microscopic point of view. A high-resolution X-ray CT scanner is utilized to get the images of pore structure and trapped gas bubbles inside the sandstone cores. Using image analysis software, statistical porosity and trapped gas saturation are obtained. Almost the same results are obtained for both vertical and horizontal cores. Porosity fluctuates with the layered structure, and correspondingly, trapped gas saturations fluctuate with the porosity. Most of the injected gas would be trapped in dense layers. Besides, Trapped gas bubbles are examined to be stable against the elevated capillary number from 1.0×10^<-6> to 1.0×10^<-5>.
