B304 核磁気共鳴を用いた岩石内CO<SUB> 2</SUB>流動・溶解現象の可視化

Abstract

This paper describes experimental research on application of nuclear magnetic resonance (NMR) to the measurement of two-phase flow of supercritical carbon dioxide (CO 2) and water in Berea sandstone and to the detection of CO2 concentration solved into water contained in porous media. We used a magnetic resonance imaging (MRI) technique to directly visualize the distribution of water injected into Berea sandstone containing supercritical CO 2. In-situ water saturation distributions in a Berea sandstone core were successfully visualized at conditions that simulate those at 700-1000-m depths in an aquifer. By applying a coreflood interpretation method to our saturation data, we could evaluate the effect of viscosity, capillary pressure, and buoyancy on two-phase flow in sandstone. Next, we developed a non-invasive measurement technique to quantify the amount of CO2 solved in water in porous rock by means of NMR. This technique could be applicable to monitoring of CO2 around boreholes as well as laboratory experiments such as the diffusion and convection of CO2 in water in porous rock.