Logging Evaluation Method Of Physical Properties And Gas-bearing Capacity In Shale Gas Reservoir

Shale gas gains widespread attention as a new type of clean and efficient energy and plays an important role in the ongoing reform of energy structure in China.Shale gas is a kind of self-generating and self-storage unconventional gas,which is stored in pores of shale in the form of dissolved state,adsorbed state and free state.Since the characteristics of tight of shale formation,low porosity,complex rock composition and diversity of gas forms,the conventional logging interpretation methods are inaccurate for shale gas reservoirs.This paper proposes a special interpretation method of shale gas formation for the study area.This paper chooses the shale gas reservoir of Longmaxi formation in ZhaoTong as the research object,evaluates the porosity,permeability,water saturation,fracture,and adsorption content and free gas content for shale gas formation based on logging data and rock physics experiment,establishes interpretation model and evaluation method of physical properties and hydrocarbon content for the study area.In terms of shale gas logging characteristics,this paper analyses the conventional response characteristics of rich organic shale reservoir,shale gas bearing response characteristics and the characteristics caused by the low resistivity anomalies;This paper also expounds the characteristics of FMI,nuclear magnetic resonance(NMR),ECS,Sonic Scanner in shale reservoir.In terms of property assessment,this paper introduces the methods of measuring petrophysical parameters in laboratory,establishes evaluation model of porosity,permeability,saturation using the core physical properties for scale based on logging data in study area.Simultaneously identification of formation fracture of shale formation is researched by dual lateral resistivity and FMI.In terms of isothermal adsorption experiment,this paper expounds the shale adsorption mechanism,and summarizes the influence law of shale isothermal adsorption feature on total organic carbon content,organic matter maturity,temperature,water and other factors through the analysis of experimental results.In terms of experiment of hydrocarbon content,this paper expounds the methods to measure the air content of loss desorption and residual in the experiment and the causes of error,analyzes the influence factors of gas content of formation.In terms of hydrocarbon content evaluation by logging,this paper calibrates the model of adsorption gas according to the law of influencing factors,measures porosity,saturation based on physical properties and establishes free gas content model combining with temperature and formation pressure.Finally,the total amount of gas bearing formation is calculated and verified by the air content determination experiments...