Pore Characteristics of Gondwana Shale of Eastern India

Abstract

A complete pore characteristic of the Indian Gondwana shale is studied by combining laboratory experiments and numerical modeling. Mercury injection capillary pressure (MICP), nitrogen gas adsorption (N2GA) and scanning electron microscopy (SEM) are the primary laboratory methods used to evaluate the pore characteristics. The N2GA and MICP were coupled to estimate the pore size distribution (PSD) of Indian Gondwana shale for the first time. The estimated PSD of Gondwana shale varies between 0.5 nm to 100 µm and most of the pores of the samples fall in the micropore and mesopore category. The porosity of Gondwana shale, measured using MICP, varies from 1.13 to 8.01%. The SEM micrographs and hysteresis pattern of isotherms reveal the presence of cylindrical, ink-bottle and slit shape pores in the samples. The BET (Brunauer-Emmett-Teller) surface area of pore for Gondwana shale varies from 3.42 m2/g to 21.5 m2/g. The FHH (Frenkel-Halsey-Hill) fractal model suggests that the Gondwana shale exhibits two types of fractal dimensions with highly complex pore geometry. The adsorption capacity of Gondwana shale is affected by the clay content. This paper attempted a different interpretation approach using experimental data and concluded that Indian Gondwana shale has high gas storage capacity.