Adsorption characteristics of shale reservoirs in the Jingmen area and application of adsorption potential theory

Organic carbon content, carbon isotope analysis of kerogen, X-ray diffraction and low-temperature CO₂+N₂ adsorption tests were usedto investigate the conventional geological properties and pore characteristics of shale samples from the Jingmen area. The results show that the shale samples have high organic carbon content, high maturity, and well developed pore structure. A gravimetric method was used to make isothermal adsorption experiments, and an isothermal adsorption model was established to measure the effect of moisture and temperatureon adsorption. Results show that the shale samples have good adsorption properties with an average adsorption volume of 2.52 mL/g. A Langmuir model fits well with the adsorption curves. The adsorption capacity of shale samples decreases as moisture content and temperature increase. Adsorption potential theory was used to explain the controlling factors, and the results showed that it is more useful when adsorption potential is high.