Research On The Characteristics And Prediction Of The Lower Permian Carbonate Reservoirs In The Daxingchang Area Of The Sichuan Basin

Daxingchang area is developed in reservoir and rich in oil and gas at the Lower Permian Period,but reservoir prediction is more difficult because of the complex structure,the development of faults and the low degree of exploration.Based on three-dimensional seismic data,the structure of the study area is analyzed and the Lower Permian reservoir is predicted on the basis of reservoir characteristics.Firstly,on the basis of three-dimensional seismic data and logging data,the meticulous interpretation of the study area is carried out.The structural and fracture distribution characteristics are analyzed.Then,combined with drilling data and geological background,the characteristics of Lower Permian carbonate reservoirs in Daxingchang area are studied.Finally,the reservoirs and fractures are predicted by wave impedance inversion and multi-attribute analysis.The favorable reservoir areas are divided due to the comprehensive prediction results.Through the research,the following understandings have been obtained:The latent structure of Daxingchang is a narrow anticline with nearly north-south direction,and the structure of Maokou Formation is similar to Qixia Formation;The platform beach developed during the Lower Permian period,which is conducive to the development of reservoir;The lithology of reservoir dominatly is bioclastic limestone,locally developed dolomite.It if poor of the reservoir physical properties,and the fractures and karst caves have been developed;It shows weak amplitude and random reflection of seismic features,and low gamma and mediumlow wave impedance of logging features;Combined with reservoir,fracture prediction results and structural analysis,the favorable area of Maokou Formation is about 25.3 km2,and the Qixia Formation is about 28.9 km2.It is mainly distributed in the central and southern part of the structure with strip shape,which corresponds to the distribution of gas wells.It provides a basis for exploration and development.