Application of characteristic gas adsorption curves for shales

The study of the gas adsorption capacity of shales is a basic tenet of shale gas research.The Langmuir's volume is an important parameter when evaluating the gas adsorption capacity of shales.The adsorption potential theory was applied here to study the gas adsorption capacity and characteristics of the adsorption systems in shales for different gases.Experiments showed that different adsorption curves were obtained for the adsorption systems of shales and different gases.These curves were not influenced by temperature and so could be used in the prediction of isothermal adsorption curves.Some shale samples were collected from the Wufeng and Longmaxi formations in the southeastern Sichuan Basin, and were tested to predict their adsorption capacity under formation conditions.It was found that the adsorption amount was obviously different from the Langmuir's volume, which demonstrated the controlling effects of temperature and pressure on the adsorption capacity of shales.