Research On The Stratigraphic Sequence And The Sedimentary Facies Of The Upper Member Of Kepingtage Formation In Central Tarim Basin

On the basis of the core, well-logging, and seismic data, using sequence stratigraphy, sedimentology, reservoir geology and other disciplines of theory and methodology, combined with geology and seismic, overall and local research and study, the thesis is mainly on studying the upper member of Kepingtage formation in central Tarim Basin, building up the sratigraphic sequence framework of the study area, establishing the development and distribution of depositional systems and making a preliminary analysis and forecast on the reservoir as well. The research will have important guiding significance on the oil and gas exploration in this region.1. Establishment of the stratigraphic sequence framework of the upper member of Kepingtage formation in central Tarim Basin. Using the seismic, well-logging, core, etc, the upper member of Kepingtage formation is divided into two third-order sequences. The third submember and the second submember equal to the Sequenceâ… , The first submember of Kepingtage formation and the lower member of Tataaiertage formation equal to the Sequenceâ…¡.Each sequence consists of a transgressive system tract and a highstand system tract, without a lowstand system tract. The third submember equals to the transgressive system tract of Sequencâ… , The second submember equals to the highstand system tract of Sequence I . The first submember equals to the highstand tract of Sequenceâ…¡.2. Analysis on the sedimentary models, deposition systems types and characteristics of the sedimentary facies of the upper member of Kepingtage formation in central Tarim Basin. The depositional systems of the upper member of Kepingtage formation are divided into three types, namely, the tidal flat sedimentary system, the coastal sedimentary system, the braided-fluvial delta system. The coastal depositional systems mainly distribute in Tabei area, which can be divided into upper shoreface, middle shoreface, lower shoreface and shallow shelf. The tidal flat depositional systems mainly distribute in Tazhong area. They can be divided into supratidal zone, intertidal zone and infratid zone, which are further subdivided into supratidal mud flat, intertidal mud flat, intertidal mixed flat, intertidal sand flat and channels in infratid zone. The favorable sand body reservoirs are developed in intertidal sand flat and channels in infratid zone. Depositional systems have significant regional zoning.3. Basically description of the development and distribution of the favorable sand bodies of Kepingtage formation in central Tarim Basin. The favorable sand bodies are mainly developped in transgressive systems tracts, sand bodies have zoning property on the plane. The favorable sand bodies of the third submember is mainly distributed from Well Yangwu4 to Well Yihe4, Well Tazhong86 to Well Tazhong31 in Tazhong area. The favorable sand bodies of the first submember are mainly located from Well Xiaotangl to Well Juemal in Tabei, Well Tazhong86 to Well Tazhong31 in Tazhong.