Study On Logging Interpretation Method Of Shale Gas Reservoir In Shanxi Formation Of ZT Block In Qinshui Basin

In order to serve the exploration and development of shale gas in the coal formation of the Qinshui Basin and improve the interpretation of shale gas reservoir logs,it is particularly important to study the interpretation methods of shale gas reservoir logs.Based on extensive literature research and data collection in the ZT area,this paper firstly sorted out the current status and key technologies of shale gas reservoir logging interpretation methods,carries out pre-processing of logging data,analysis of reservoir logging response characteristics and stratigraphic delineation and comparison studies,and establishes an accurate stratigraphic comparison framework in the area.Secondly,based on the test data and logging data,a model for predicting the mineral fraction,geochemical parameters,physical parameters and gas content of shale was established,based on which model selection was carried out,and the analysis of the planar spreading characteristics of each parameter was completed.Again,a model for predicting shale rock mechanical parameters and brittleness index was developed and a planar spreading map was drawn,and finally a study on the interpretation method of shale gas reservoir logging was realized.The study shows that the natural gamma-acoustic time difference intersection method is effective in identifying lithology,and the mud shale logging response is characterized by "four highs and two lows";the stratigraphic comparison shows that the thickness of the Shanxi Formation is stable,and the overall trend is upward from northwest to southeast.The main minerals in this area are clay minerals and quartz,and the multi-mineral model optimization method is effective in calculating mineral fractions,and the quartz content and clay mineral planar distribution characteristics are in a "complementary" relationship.The PCA-GBDT model calculates the total organic carbon content better than the natural gamma-density model method and multiple regression analysis,with an overall higher total organic carbon content;the organic matter is at an over-mature stage and has poor hydrocarbon production potential.The shale reservoir is characterized by ultra-low porosity and ultra-low permeability,and the multiple regression analysis method has a better effect in predicting porosity.The strength and elasticity parameters of the mud shale show an overall "saddle-like" characteristic,with the long-axis direction nearly northwest-southeast;the brittleness index is 37% on average,showing high values in the southwest direction and decreasing in the northwest and east directions.The research results of the paper provide important technical and results support for the study of shale gas reservoir logging interpretation methods in the ZT area,and the related technical methods have certain reference significance for the comprehensive geological study of shale gas in neighbouring areas.