Research On Lower Permian Reservoir Characteristics Of Daxingchang Structure In Southwestern Sichuan

The Daxingchang construction is located in the southwest of sichuan basin.In recent years,high yield industrial airflow of DS001-X1,DS001-X3,DS001-X4 has been successively drilled in the Lower Permian Plq?Plm Formation,showing a good prospect of natural gas exploration.In this paper,the Lower Permian reservoir in Daxingchang structure is taken as the research object,based on a large number of field outcrops,geophysical data,drilling and logging data,by combining the macro-observation with micro-analysis,dividing and comparing the formation,the characteristics of reservoir of Plq?Plm Formation and its main controlling factors are analyzed,the distribution characteristics of the reservoir are predicted.Research shows that:? Drilling and field profile reveal the thickness of the Lower Permian Plm Formation is 310?350m in the area,the thickness of the Lower Permian Plq Formation is 100?120m,which have stable distributions the thickness of the Lower Permian is quite similar to that of the whole southwest Sichuan.? The sedimentary stage of Daxingchang structure in P1q?P1m Formation is located in the open platform facies deposit,Sedimentary microfacies of beach and inter beach sea are developed.? The reservoir types of P1q Formation in this area are fractures-pore type reservoir and pore-seam type reservoir,and lithology is dominated by crystalline dolomite and bioclastic limestone.Reservoir heterogeneity is strong.?Many factors such as sedimentary facies,dolomitization,dissolution and structural fracture control the development of reservoirs in P1q?P1m Formation,granular carbon is the basis for the scale development of reservoir,dolomitization and dissolution improved the permeability of reservoirs,structural fracture and associated dissolution are the keys to reservoir development and high yield of gas well.The dolomite reservoir in the south flank of Daxingchang structure is developed,test gas,dolomite of the formation in high site gradually disappeared,possessing the condition of forming structure and lithologic complex trap and has a certain potential for exploration and development.