The Depositional Facies Evolution And Reservoir Prediction On Pingdiquan Formation Of Permian In Wucaiwan Depression Of Junggar Basin

Pingdiquan formation is the major source rocks in Wucaiwan Depression ofJunggar Basin, mainly developing a set of gray-green conglomerate, black to darkgray mudstone, gray fine sandstone mixed with dolomitic mudstone, calcareoussandstone and oolitic limestone. Longitudinal oil-bearing property is controlled bylithology distribution, with no significant boundary of source，reservoir and cap；andthe hydrocarbon shows largely and continuously, which is characterized byself-generation and self-reservoir.The first member of Pingdiquan formation ofCai-201well was shot, wining industrial flows by recovery test,which reveals thatthere is still a good prospect for oil and gas exploration. The important issue of oil andgas exploration in the region is to find out the distribution of favorable reservoir andsedimentary facies urgently, to speed up the exploitation in the area.On the basis of well cores, drilling and logging data analysis, combined with theresults of seismic data interpretation, under the guidance of seismic sequencestratigraphy and sedimentology, the thesis re-determined the tresection boundaries ofPingdiquan formation,built the isochronous stratigraphic framework of thefirst,second,third members of Pingdiquan to study the expanding characteristic ofstratum and understand the sedimentary evolution,and make reservoir prediction forthe three members of Pingdiquan formation and next recovery test Wellsrespectively.Main conclusions of this thesis were listed as follows:(1) According to the isochronous stratigraphic framework of the study area,guided by the principle of high resolution sequence stratigraphy, the short, mediumand long-term cycles of the three strata were divided, studies showed that the threestratums include many short-term and mid-term cycles, the first and second membercan be divided into a long-term transgression cycle, the third member can be dividedinto a long-term regression cycle.(2)Lining the analysis of heavy minerals and ancient landforms, the threestratigraphic provenance comes from three directions: the south of Dinan fault zone,the west of KeLaMeili Mountain and the southwest of KeLaMeili Mountain. (3)By a detailed division of the lithology in the study area, the contour parametermaps of three stratums were made, combined with seismic attributes fittingconstraints, three stratums have inheritance in sedimentary framework, mainlydeveloping the braided delta. Underwater distributary channel and sheet sand are welldeveloped in the first member of Pingdiquan formation, and widely developed in thesecond member, braided stream dam developed in the third member.(4)Through physical property statistics and multi-parameter clustering analysis,combined with the range of Pingdiquan trap, favorable reservoir distribution areawere lay out in each member,which were thought that the braided delta front withunderwater distributary channel and braided bar are favorable reservoir facies. Thenfour next recovery test Wells were put forward.By a comprehensive study of sequence, sandbody correlation, sedimentary faciesand the distribution of favorable reservoir of the Pingdiquan formation,this thesisprovided reliable basis for exploration of oil and gas reservoir and recovery test instudy area.