Research On Gas Content Characteristics Of Shale Gas Reservoirs In Yushe Area Of Qinshui Basin

The potential of shale gas resources in Yushe area is emphasized by Shanxi provincial government day by day.In order to support exploration and development of shale gas,an urgent need to carry out logging comprehensive evaluation of shale gas reservoir in Yushe area.Therefore,this paper focuses on research of Shanxi formation and Taiyuan formation which in Carboniferous Permian and study of logging evaluation of shale gas content characteristics to serves logging comprehensive evaluation research.Based on a number of literature research,this thesis summarized the main methods of shale gas reservoirs logging evaluation.By collecting geological data,core test data and logging data in Z area of Yushe,thesis developed stratigraphic division and comparison firstly.And then,the geological characteristics,reservoir characteristics and logging response characteristics of shale gas reservoirs in research area were summarized in paper.After that,the logging prediction models of mineral composition,total organic carbon content,physical parameters and reservoir gas content had been established.Based on above data,paper carried out an analysis of influencing factors of gas content in shale gas reservoirs,and the model of gas logging interpretation which fit Z area was eatablished.And finally,the gas content characteristics of shale gas reservoir in study area were studied.The results have shown that the second reservoirs and the third reservoirs(Shanxi formation and Taiyuan formation)are the main targets for this research among the four shale gas reservoirs in Z area.The target lithologies in Z area are dominated by shale,fine siltstone,silty mudstone,carbonaceous mudstone,limestone and coal.The major mineral components of rocks are clay minerals and quartz minerals.Based on core data and logging data,clay,quartz and carbonate rock mineral calculation models were established in this paper.The statistical data of the target stratum geochemical test has shown that,the shale in research area is medium-good source rock,organic matter belongs to type III and it is in the phase of high maturation-over maturation.Through comparative analysis of ?lgR method,double argillite content method,and multi-regression method of sensitive conventional logging curves,multiple regression analysis method which calculation results higher was used to evaluate the total organic carbon content in study area.Based on actual data of physical property analysis in Z area,the statistical analysis method and empirical model method are used to establish porosity and permeability evaluation models.Temperature,formation pressure,porosity and etc affect free gas content,and total organic carbon,temperature,formation pressure and etc affect adsorption gas content.And this paper used the gas saturation method and the improved KIM equation method to calculate free gas and adsorption gas.The gas saturation method was used to evaluate free gas content,the improved KIM equation method was used to evaluate adsorption gas content,and desorption method to evaluate the total gas content in study area by comparing multiple evaluation methods,the gas content calculation results and experimental results are in good agreement.Combined with desorotion experimental data and logging data in research area,paper seletcted the gas content calculation method which has higher accuracy,and also carried out research on gas content calculation and distribution characteristics in research area.