Methane adsorption and pore characterization of Indian shale samples

Understanding adsorption behavior of methane in shale is important for predicting the gas reserve and evaluating reservoir potential. This paper presents the methane adsorption behavior of three gas shale samples of Gondwana and KG basin of India. Adsorption experiments are conducted on as-received samples at a temperature of 40 °C to a maximum equilibrium pressure of approximately 9.5 MPa. The methane adsorption data are applied to test the applicability of Langmuir isotherm model. It was observed that the experimental adsorption data for Parbatpur and KG shale samples did not follow the Langmuir isotherm model, with deviation from the model value more than 10%. Although the experimental adsorption data of Salanpur sample broadly followed the Langmuir model, the deviation from the model value was more than 5%, implying the Langmuir model is not very accurate. Pore characterization study was also carried out to understand the pore structure of the shale samples. The pore characterization suggested that porosity of Indian gas shales are dominated by meso- and macro-pores.