Reservoir Characteristics And Evaluation Of Tengxia Member In Zhamu Area Of Baiyinchagan Depression

Baiyinchagan Depression has been exploring for more than 30 years.Now the exploration direction has changed from structural reservoir to lithologic reservoir.Based on the data of core,thin section,casting thin section,cathodoluminescence,scanning electron microscopy,well logging and mud logging in Zhamu area,the basic structural characteristics and evolution,sedimentary characteristics,sedimentary facies and their distribution,diagenesis of Tengxia section in Baiyinchagan Zhamu depression are studied,and the reservoir is evaluated.The main achievements are as follows:lithic feldspar sandstone and feldspar lithic sandstone are the main rocks in this area,and coarse clastic rocks are generally gravel-bearing,poor sorting and close transportation distance;after comprehensive analys is of rock and mineral characteristics,structural characteristics,sedimentary structure characteristics,grain size characteristics,sand-to-ground ratio and logging facies of sedimentary rocks in Tengxia Member,the types and distribution of sedimentary facies in Zhamu area are summarized facies.River delta develops in slope zone,fan delta develops in steep bank,slump fan and normal lacustrine facies develops in the center of trough zone;clastic rocks of Tengxia member in Zhamu area are in middle diagenetic A stage,and diagenesis is mainly mechanical compaction,cementation and dissolution,the latter two play a key role in reservoir;reservoir pore of Tengxia member is dominated by intergranular pore;reservoir of Tengxia member is mainly located in depth 800-23.00 m,the range of porosity change is 3%-23%,and the range of permeability change is 0.05-700×10^-3?m² The physical property of reservoir decreases with the increase of depth.Solution and cementation are the most important factors to control the physical property of reservoir.Lithology,depth,horizon and sedimentary facies also obviously restrict the physical property of reservoir.