| Shale gas as one of the hotpots of unconventional energy development,the characteristic of seepage is particularly important for improving the gas reservoir recovery.Because the shale reservoir has the characteristics of low permeability,slow gas desorption and long production cycle,on the basis of the traditional reservoir reconstruction,it is necessary to explore the new technique of acoustic vibration to promote the desorption of shale gas,thereby increasing the recovery of shale gas reservoirs.Based on the experimental study of shale gas acoustic shock,this paper studies the adsorption and desorption laws of shale gas under the action of sound field,and establishes the model of shale adsorption methane to guide the production of shale gas reservoir.Firstly,the lithologic characteristics of shale reservoirs,shale mineral composition and pore characteristics are analyzed to study the lithologic basis of acoustic shock experiment of shale reservoir.Then,the permeability tester is designed by using the pulse attenuation method.The results show that the ultrasonic wave contributes to the improvement of shale permeability.Secondly,the shale rock samples were subjected to isothermal adsorption and desorption experiments under sound waves,and the isothermal adsorption data of the shale after correction are fitted by Langmuir,Freundlich,BET and D-R isothermal adsorption models respectively.Finally,we establish a model of shale adsorption methane under the action of the sound field considering the excess adsorption capacity,and the isothermal adsorption data of the experimental rock samples were fitted and analyzed.In this paper,combined with experimental and theoretical analysis,the effect of acoustic effect on shale seepage and desorption is studied deeply,which provides a basis for further analysis of the action law of acoustic shock in shale reservoir.The results of the study can guide the production of shale gas reservoir to a certain extent. |
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