The fast spin echo Magnetic Resonance Imaging technique is an appropriate imaging tool for the direct and quantitative evaluation of two-phase flow of supercritical CO2 and water in porous media at sequestration conditions. Fundamental characteristics of the two-phase flow process such as the CO2 frontal, the velocity of CO2 frontal, residual water saturation, onset of fluid flow instabilities (CO2 fingering and channeling) due to fluid viscosity, buoyancy and porous media conformance problems, can be accurately detected using the MRI technique.
CO2 storage in depleted oil and gas reservoirs or aquifer is considered to be one of the most practical options for reducing CO2 emissions in the atmosphere and has been practiced in different locations worldwide. At depths below 700m, supercritical CO2 has a density similar to liquids, but it is still lighter than the saline formation fluids. The upward buoyancy force may cause the sequestered CO2 flow back to the surface. The behavior of immiscible two-phase flow of supercritical CO2 and water in porous media should be understood and the necessary data should be obtained for assessing the safety and validity of geological sequestration of CO2. Suekane et al (2004; 2005; 2006; 2009) have done many researches on this area. However, more researches are required to further understand the complexity of the two-phase flow. The aim of this paper is to understand the behavior of immiscible twophase flow of water and supercritical CO2 in porous media. This article addresses the application of magnetic resonance imaging (MRI) technique to capture the images of water displacement by supercritical CO2 in high-permeability sand-pack models at temperatures and pressures that approximate aquifers at a depth about 800m.
A simplified schematic diagram of the experimental setup is shown in Fig. 1.
