The Cretaceous Reservoir Characteristics Difference And Main Controlling Factors In KeShen Block Of Kuqa Depression

The deep and ultra-deep fractured tight sandstone reservoirs of the Cretaceous Bashijiqike Formation in Ke Shen Block of the Kuqa Depression have the characteristics of large depth,low matrix porosity,low permeability,and structural fracture development.This study is based on geological data such as core data,normal rock slice,cast slice,matrix CT,electron microscopy scanning,mercury intrusion data,conventional logging,and image logging.This paper by studying the maximum pore radius,face ratio,fracture line density,effective opening,and filling degree to study the reservoir and penetration space difference.By studying pore throat coordination number,maximum pore throat radius,and average pore throat radius to study reservoir pore throat difference.By compring the type and content of cement and the particles contact relationship to study the difference of reservoirs diagenesis.The results show that in the same row of structures,the reservoirs in the west to east direction have obvious differences and strong regularity.The reservoir from west to east has gradually become better.In the south to north direction the reservoir overall get worse to south.There is obvious differences in different well blocks reservoirs and various parameters fluctuated between the block with less regularity.In the vertical direction reservoir porosity is weakly affected by burial depth.The early and long-term shallow burial and the late rapidly and deep burial have certain protective effects on reservoirs.Comprehensive analysis suggests that the difference in reservoir properties is controlled by sedimentary microfacies and lithology,structural extrusion,dissolution and burial ways.In the same row of structures,the reservoirs characteristics difference in west to east direction mainly controlled by sedimentary microfacies and lithology.In the south to north direction mainly controlled by structural extrusion,and in the vertical direction mainly controlled by erosion and buried ways.