The Main Controlling Factors Of Reservoir In Xiashihezi Formation Of Shilijiahan Zone In Hangjinqi Area

Shilijiahan area is located in the south of Hangjinqi area of Ordos Basin,with the Poerjiang fault as its northern boundary.It has a large amount of natural gas resources.However,the gas reservoirs in this area have the characteristics of low porosity and low permeability,and the reservoir heterogeneity is strong,resulting in no obvious gas-water differentiation,complicated gas-water distribution and complicated reservoir formation mechanism,which restrict the further exploration in this area.Therefore,based on the geological characteristics of the study area,through the comprehensive study of drilling,logging,gas testing and test analysis data in this area,The gas-water distribution characteristics and main controlling factors of Xiashihezi Formation in Hangjinqi area are defined.The results show that most of the natural gas in Shilijiahan area belongs to maturation-high mature coal-type gas,and mainly comes from humic kerogen formed under brackish water.The typical braided channel sand body is developed in Shilijiahan area.The sand body with a large area of transverse distribution in section 1 of Xiashihezi is an effective transport system.Two periods of accumulation in Shilijiahan area correspond to two periods of peak gas.Source and reservoir allocation,hydrocarbon generation intensity,migration and differential uplift jointly control the overall distribution of gas and water,and the distribution and preservation conditions of sand bodies and sedimentary microfacies control the local accumulation of natural gas,forming an accumulation belt in the Duguijahan region.