Investigation into the pore structures and CH₄ adsorption capacities of clay minerals in coal reservoirs in the Yangquan Mining District, North China

Abstract The rising energy demands worldwide and difficulty in developing novel clean sources have greatly stimulated the exploitation of coalbed methane. Clay minerals are common fractions coal; thus, understanding their CH 4 adsorption capacities pore structures is vital. In this study, coal, parting, roof, floor samples were collected from Yangquan Mining District. mineral compositions, capacities, analyzed using X-ray diffraction, isothermal method, low-temperature N 2 respectively. results indicated that organic matter had a much higher capacity (33.80 cm 3 /g, 35°C) than clay minerals. various significantly different, with smectite (18.01 /g), kaolinite (5.81 mixed-layer illite-smectite (4.47 illite (2.08 /g) present decreasing order. sizes consisted <6 nm, six size groups (Groups 1–6) identified PSD patterns. These associated different We propose mainly influenced by structures, which turn species formation processes. Furthermore, conversion to illite, illitization smectite-illite, exerted negative effect on capacities.