Shale gas is mainly composed of adsorption gas and free gas.Adsorption gas content directly affects the geolo-gical reserves and well production for a shale gas reservoir.In order to accurately measure adsorption gas content

isothermal adsorption experiments were performed within temperature range of 25-45 ℃ and pressure range of 0-8 MPa on the Longmaxi Fm shale in South Sichuan Basin.Results indicate that shale adsorption capacity decreases as temperature increases.In addition

shale adsorption isotherms at different temperatures were calculated by using the simplified local density (SLD-PR) method and compared with the experimental results.The comparison shows that this method can be used to calculate shale adsorption isotherm.The SLD-PR method can be used to predict shale adsorption isotherm under reservoir pressure and temperature conditions

thus overcoming the disadvantage that the errors of isotherm experimental measurements under high temperature and pressure are large.Comparison between the calculated adsorption gas content by the SLD-PR method and that by the Langmuir method indicates that the former is more accurate and reliable than the latter.