Study On Calculation Method Of Shale Gas Content In Wulalike Formation,Western Margin Of Ordos Basin

In recent years,great breakthroughs have been made in ordovician Marine shale gas exploration in Ordos Basin,northern China.Gas content calculation is an important basis for regional shale gas reserve evaluation and single well production prediction.In this paper,conventional logging data and core test analysis data were collected in the study area.Based on the calculation of reservoir porosity,total organic carbon content and water saturation,the influencing factors of shale gas content in wulalike Formation in the western ordos Basin were analyzed and the calculation model was established.Firstly,this paper summarizes the methods of shale gas reservoir logging evaluation,the calculation methods of reservoir parameters and the difficulties of shale gas logging evaluation in the study area on the basis of domestic and foreign literature research,and determines the research ideas and methods.Then according to the literature to understand the geological structure characteristics of the study area,through a series of experimental data such as rock physics experiment,the geochemical characteristics,mineral components,physical properties,gas,logging response characteristics of the target layer in the study area are studied and analyzed.On this basis,a series of modeling work is carried out for shale gas reservoir evaluation parameters in the study area:(1)The TOC content is obtained by ?lgR method and multi-parameter regression calculation method,and compared and optimized;(2)Using simmonds equation and volume model method to calculate formation water saturation;(3)The porosity of reservoir was calculated by multiple linear regression method;(4)By using ECS logging data calibration,a multiple linear regression model was established to calculate the clay mineral content in the formation,and a complex lithologic volume model was used to calculate the mineral composition.Eventually the parameters required for the accurate calculation of logging evaluation,respectively analysis the influence factors of the adsorption gas and free gas content,build based on the factors affecting gas content of shale gas reservoir calculation model for gas content: use conversion method to calculate the free gas content,gas saturation with Langmuir isothermal adsorption equation as the core to establish model for calculating the adsorption gas content.When the gas content calculation method used in this study is put into use,the error range between the calculated gas content data and core test data is small,indicating that the gas content calculation model constructed in this study has good applicability in the research area.