貯留層マネージメントに向けたデジタル岩石の利用

抄録

Digital rock physics combines modern microscopic imaging with numerical simulation for analysis of the physical and hydrological properties. Recent technology developments of X-ray microcomputed tomography

（micro-CT） as well as computational capacity for numerical simulation enable us to apply digital rock physics to natural

rock samples. Using digital rock models, we study porous flow, fluid-solid interaction, interfacial phenomena, elastic and inelastic deformation, and mineral precipitation within real pore space. This approach allows us to estimate both hydraulic and elastic properties in various reservoir conditions. Here we mainly show the application of digital rock physics for carbon capture and storage （CCS）. The behavior of CO₂ inside pore space can be characterized as two-phase or three-phase flow in a porous media system, which is usually influenced by interfacial tension, pore structure, pressure, wettability, etc. Therefore, we believe that digital rock physics contributes to reveal multi-phenomena in porous medium occurred in the CCS project. To characterize hydraulic properties of reservoirs using geophysical data, we can use digital rock physics to obtain the relationship between hydraulic and geophysical properties. We usually use analytical models or empirical relations to estimate physical/hydraulic properties from geophysical properties（ e.g., seismic velocity）.

However, the analytical models（ e.g., differential effective medium theory） can be applied only for the simplified pore geometry （e.g., crack）. The digital rock physics can construct the relationship between elastic properties and hydraulic properties by considering realistic pore geometry and in various reservoir conditions. The relation contributes to monitoring and modeling of the reservoirs.