ABSTRACT:

We conducted experimental study on multi-phase flow behavior consisting of supercritical CO2 and water in porous media. Grain size was changed as an experimental parameter in order to consider the effect on permeability characteristics. Using obtained experimental data such as discharge rate of fluids, differential pressure between inlet and outlet of sand column, we conducted a numerical simulation for laboratory-scale experiment in order to clarify permeability characteristics of supercritical CO2 in porous media. As relative permeability model, the extended Corey model that Nkrg and Nkrw as indexes were introduced into the original one was used. Through numerical analysis, the shapes of relative permeability curves that allowed us to reproduce CO2-water flow multi-phase behavior were optimized.

INTRODUCTION

Both aspects of risk and benefit are very important in understanding the feasibility of CO2 geological storage at specified situation. Various types of benefit of geological carbon storage, compared with ocean and atmospheric discharge, can be easily understood in the scientific aspect of global environment and the economical aspect of CDM. However, the assessment of risks caused by carbon capture and storage (CCS) would be hardly undertaken, because of difficulties to determine the end points and parameters for estimating ecological and human risks. In order to achieve transparent risk governance for any stakeholders who are involved in CCS project, it is necessary to develop the general and/or common framework, enable to be fully communicated within any party of concern. It is supposed that the leakage of injected CO2 as the principal hazard due to the existence of fault occurs when CO2 storage in an aquifer is targeted (Benson et al., 2005; Færseth et al., 2007). The quantitative estimation for the amount of storage and leakage of injected CO2 is very important for risk assessment of CCS.

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