Consecutive Interpretation Of Seismic Data And Reservoir Study In The Shinan Area Of ??Beas, Northwestern Sichuan, Sichuan Basin

The source rocks of the Permian System and Triassic System in the northwestern Sichuan Basin have favorable conditions.This area have favorable sedimentary facies belts,large-scale distribution of bioclastic beach facies,and the structure spread in rows and belts.And there are plenty of traps.Located in the Jiulongshan to Zhongba tectonic group of the low-tempered structural area of the Middle-Lower Paleozoic in northern Sichuan,the southern part of Shuangyushi Area spans the Longmen Shan piedmont zone of bruchfalten and this is the region with complex geologic structures and geomorphology.According to the analysis of current geological conditions,there are favorable tectonic conditions for oil and gas accumulation.Since 2014,Southwest Oil&Gas Field Company has conducted multiple rounds of 3D seismic surveys in the area of the Shuangyushi Area.In order to enhance the exploration activity and evaluation of reservoir in Shuangyushi Area,it is very important to carry out successive interpretations of seismic data and to predict the reservoir.In this study,three-dimensional seismic were used to finely implement the relationships among the scale of traps,location of highland locations,fault distribution patterns,and the structures in the southern part of Shuangyushi Area.The piedmont zone of Longmanshan has a strong pushover effect.The subsurface structure is complex and the faults are developing.Especially,the northwestern region of the area is severely cut,there are numerous cliffs,the contact relationship between structures is complex,and also the seismic wave field is complex.It is difficult to dividing each structural block correctly,and It is also difficult to make a reasonable combination of faults and break points.Five techniques are used in this study,the interpretation of geological hat,establishment of structural models,comprehensive interpretation of sesimic and geology,interpretation of faults and pre-stack depth migration profile interpretation.This study has finely interpreted the target stratums in this area,clarify the potential contact between structures preliminarily.At the same time,by comparing the pre-stack time migration profiles at different levels in the interpretation zone,the horizontally overlapping interpretation profiles,the pre-stack time migration interpretation profiles,the pre-stack depth migration interpretation profiles,and the tectonics results maps,combined with the research result of drilling and geology synthesis in the region.The results of the study meticulously portrayed the vertical and horizontal distribution of the reservoirs of Maokou Formation and Qixia Formation of Permian System,and Guanwushan Formation of Devonian System and compiled the thickness maps of different layers,the favorable topography of paleotopography and the distribution of the favorable facies of the reservoir.This study also developed three-dimensional prediction based on seismic prestack and poststack reservoirs,fluids and fractures,and compiled the the maps of predicated reservoirs distribution,the maps of favorable oil&gas reservoirs distribution,and the maps of predicated fracture distribution of six layers of reservoirs,which includes Maokou Formation and Qixia Formation of Permian System,and Guanwushan Formation of Devonian System.Based on the original understanding of the southern part of Shuangyushi Area,the study get the further understanding in the structure of the target stratums,the scale of traps,the distribution of faults,and the detailed changes in this area:simple and few faults;faults are mainly developed in the middle structure,with high fold strength,faults developed,one new trap is discovered at the bottom boundary of the Lower Permian Maokou Formation and 34 traps are re-enforced,and the cumulation of trap area is 278.03km2.