The Adsorption Model Of Methane Adsorption In Shales At High Pressure Is Studied

Methane under the condition of formation,exceeded its own critical temperature and pressure,belong to the supercritical fluid,will no longer exist in saturated vapor pressure,will not be liquefied,adsorption also won't appear capillary condensation phenomenon.The study on the behavior of shale adsorption methane is mainly through the development of classical adsorption model.Adsorption model is a total of four categories,according to the supercritical flow reflect some studies showed that supercritical fluid will not form a multilayer adsorption in the surface of adsorbent,also won't produce capillary condensation phenomenon,and only for the monolayer adsorption or micro hole filling,the isothermal adsorption curve for ? isothermal adsorption curve.So the adsorption model of molecular dynamics and adsorption potential energy can be applied to the adsorption of supercritical fluid.On the experimental data of shale adsorption of methane by using the model description,found that the curve is not in conformity with the type ? isothermal adsorption curve shape,a phenomenon of the adsorption.According to the theoretical derivation and experimental data processing,according to the definition of Gibbs,the adsorption is divided into absolute adsorption quantity and excessive adsorption capacity,and the experiment can only measure the excess adsorption quantity.But the absolute adsorption is the real adsorption of adsorption,which has great guiding significance for production.There are three main methods: curve mapping method,assignment method and undetermined parameter.Study compares the three methods of correction,can study the adsorption behavior accurately,according to such a situation,to establish a new kind of correction methods,combined with the graphic method and the method of undetermined parameters,the correction results more in line with the adsorption behavior of real.According to the study of the different classical adsorption models,the study on the overabundance adsorption capacity is found to be unable to accurately describe the adsorption behavior of shale.Based on the characteristics of shale adsorbent,the model of half-hole width was deduced.The conditions of the hypothesis are changed,and the adsorption of the critical semi-pore size is ignored,which is more in line with the actual conditions of shale adsorption.Using the new model experiment of different block sample to study the adsorption results,the new model can very good fitting each work area the adsorption behavior of shale,the corresponding calculated adsorption phase density also accord with the actual situation of adsorption.