Abstract
Shale gas is an important field and a goal for industrial natural gas exploration under current economic and technological conditions. In shale gas reservoirs, adsorbed gas is an important part of the system that cannot be ignored. In this article, a prediction model for shale gas adsorption considering in situ reservoir conditions is established. Logging data and adsorption experimental data are used to determine key adsorption parameters in the model. Shale samples of YC2-19, YC2-20, and YC2-28 are used to carry out methane adsorption isothermal experiments to verify the correctness of the model. Sensitivity analysis of the model and adsorption prediction analysis under field conditions were carried out. The results show that (1) the adsorption capacity of organic matter is less than that of clay minerals; (2) under the conditions of actual reservoir depth, the k value has almost no effect on gas Langmuir pressure. The change of gas adsorption capacity with depth is similar to the adsorption-pressure curve; (3) the prediction model has good application results in the actual field. Based on the abnormal value of the water content correction coefficient, it can be judged whether there is an abnormal condition in the formation.