The Experimental Study On Dynamic Desorption And Diffusion Characteristics Of Shale Gas

Shale gas production in China is huge,but the recoverable of shale gas reservior is still at the lower stage.The seepage rule of shale gas reservoir is different from the conventional reservoir.The theory of seepage in conventional gas reservoirs can not be directly applied to guide the development of shale gas reservoirs.During the process of shale gas production,the resources of stable production in the middle and late stages are mainly derived from desorption of adsorbed gas,while the isothermal adsorption method can only obtain the result of equilibrium point.The intermediate dynamic process is difficult to be obtained,and the current experiment process focuses on the development of failure,And the actual production process does not match,it is necessary to study shale gas desorption systematically.This paper choose Jiannan gas reservoir as the research object,and study different factors affecting the dynamic process through the use of isothermal constant pressure experimental method,respectively.The effects of multi-stage on the desorption characteristics of shale gas were studied.The effects of temperature,pressure,particle size,TOC and depressurization on the dynamic desorption process of shale gas are obtained by a series of experimental studies.The effects of unbalanced degree and different pressure decay rate on desorption dynamic process are analyzed,It can provide some meaningful guidance to shale gas on-site production Through the system analysis and researche.Of great relevance to field development and management is knowing the contribution of each gas source to gas transport history and to ultimate gas recovery.Based on the results of this paper,the contributions of free gas and adsorbed gas could be determined.