Experimental apparatus and method to investigate permeability and porosity of shale matrix from Haenam Basin in Korea

Abstract

This study presents a new apparatus, which can simultaneously measure petrophysical properties such as low-permeability and porosity in a shale gas reservoir. Using the apparatus, the experiments have been performed to measure the low-permeability and porosity of three shale core samples, which are from Haenam Basin in Korea. As for the experimental results, porosity ranges from 4.65 to 11.6 % and the permeability measured in forward and reverse direction is 1.27E−16 and 1.32E−16 m2 for HS-1, 1.65E−17 and 1.77E−17 m2 for HS-2, and 6.91E−18 and 7.90E−18 m2 for HS-3, respectively. As a validation of measurement, regression analysis was carried out using the dimensionless pseudo-pressure between the measured data and analytical solution. The results showed that correlation coefficient of dimensionless pseudo-pressure increased to 0.95 in upstream and downstream reservoirs. From the positive results, it is found that both are approximately equal in terms of permeability and porosity. To represent the effect of geological features inside core sample on permeability and porosity, X-ray scan of the shale core samples was taken by Microfocus X-ray CT. Clearly, the value of permeability is subject to geological features such as micro-crack. This means that the micro-crack acts as an important factor in terms of permeability variation by its direction and length in a shale gas reservoir.