Difference of methane adsorption capacity of kerogen and clay minerals

Shale gas mainly occurs in organic-rich shale in the form of free gas and adsorbed gas. At present, domestic and international research on the adsorption capacity of kerogen and clay minerals to methane is still relatively weak. A method for separating kerogen and clay minerals was proposed in this paper. The difference of adsorption capacity of methane in a unit mass of kerogen, illite mixed layer, kaolinite, chlorite and illite were studied by isothermal adsorption experiments on kerogen and different clay minerals. The experimental results indicated that the order of methane adsorption capacity is kerogen>illite mixed layer>kaolinite>chlorite>illite, and the gas adsorption capacity of kerogen in some samples is greater than the sum of that of clay minerals. The methane adsorption capacity of kerogen and clay single minerals decreases with temperature. At the same tempera-ture, the methane adsorption capacity of kerogen increases with vitrinite reflectance (R_o), while clay minerals are not affected by vitrinite reflectance.