Research On Sedimentary Characteristics Of The Middle-Lower Triassic Formation In Wuxia Area, Junggar Basin

The Wuxia Area which in the northwestern in Junggar Basin is one of the containingexpected to take. It is the original place of oil and gas and the oldest exploration.Predecessors have done a lot of work in the Wuxia Area. Previous research on sedimentarycharacteristics and sedimentary evolution was rough, and it was usually based on the unit offormation. This paper is to fine describe the sedimentary evolution characteristics of Wuxiaarea. Based on the previous research, using the logging well and seismic interpretation, togo deep into sedimentary facies research. The Middle-Lower Triassic Formation containsBaikouquan Formation, Kexia Formation and Keshang Formation.The Middle-Lower Triassic Formation include3formations that are BaikouquanFormation, Kexia Formation and Keshang Formation. There are one2ndsequence boundary,three3rdsequence boundaries which can divide four3rd sequences and13system tracts.SequenceⅠ is corresponding to Baikouquan Formation, which includes LST, TST and RST,SequenceⅡ i s corresponding to Kexia Formation, which includes LST, TST, HST and RST.There is a3rdsequence boundary in the Keshang Formation, the bottom of Kexia Formationis Sequence Ⅲ that includes TST, HST and RST system tracts. The top of KeshangFormation is Sequence Ⅳ, there are TST, HST and RST.On the base of sequence stratigraphic framework establishment and sedimentary facesrecognition. There are Alluvial Fan, Fan-delta, lake and Sublacustrine fan in Wuxia Area.Alluvial fan root, fan in and fan edge, fan-delta front and plain, shore shallow lake and halfdeep lake-deep lake, in total7sub-facies and6microfacies. Based on analysis of2wellsand then combining with the logging and seismic interpretation, to have an in-depth knowledge of the facies in Wuxia area. In order have a comprehensive understand of thelandscape and lengthways changes, drawing9profile maps that4run east through west and5south through north.Through the sand thickness determined the boundaries of sedimentary facies. Mappingthe sedimentary facies for the each formation. At last draw the conclusion that: TheMiddle-Lower Triassic Formation, Baikouquan Formation Period the climate was dry, thewater was shallow and provenance, there are a lot of alluvial fan and the Fan-deltadeposition. To the Kexia Formation, lake level rised so that the fan-delta became the majorfacies. When to the Keshang Formation Period, the lake level rised again, most area becamelake lacustrine facies.