Oil & Gas Geology ›› 2013, Vol. 34 ›› Issue (1): 85-94.doi: 10.11743/ogg20130111

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Sedimentary characteristics and geophysical responses of sublacustrine fan in the Junggar Basin:a case study on the Lower Urho Formation of the Permian in the Wuba block,Karamay oilfield

Wu Tao1,2,3, Zhao Changyong3,4, Wu Caixi3, Su Yanli5, Zhou Zuoming3, Zhang Shuncun1, Shi Jian1   

  1. 1. Key Laboratory of Petroleum Resources Research, Institute of Geology and Geophysics, Chinese Academy of Sciences, Lanzhou, Gansu 730000, China;
    2. University of Chinese Academy of Sciences, Beijing 100049, China;
    3. Research Institute of Exploration and Development, PetroChina Xinjiang Oilfield Company, Karamay, Xinjiang 834000, China;
    4. Exploration Department, PetroChina Xinjiang Oilfield Company, Karamay, Xinjiang 834000, China;
    5. Fengcheng Field Operation District, PetroChina Xinjiang Oilfield Company, Karamay, Xinjiang 834000, China
  • Received:2012-05-21 Revised:2012-12-30 Online:2013-02-28 Published:2013-03-18

Abstract:

Sublacustrine fans were identified firstly in the Junggar Basin through integrated methodology of geology and geophysics.Data gathered from core sampling,testing,logging,and 3D seismic analysis of the Wuba block in Karamay Oilfield of Juggar Basin,show that the fans develop well in the lower Urho Formation of the Permian in the area.Study on the sedimentary facies,petrology and texture reveals that the fans have Bouma sequence and grain size distribution typical of turbidite deposits.Forward seismic modeling confirms the sensitive responses of the fans.The spatial distribution of fans was finely described with several seismic technologies including seismic multi-attributes,spectrum decomposition and seismic slices.The sandbodies in the fans occur as chaotic reflection,oblique reflection and lenticular reflection on seismic profiles.On plane view,they are widely distributed in clusters with good sandstone and mudstone combinations,while in space,they show lens shapes.These sandstone reservoirs and source rocks are close and in good combination,favorable for forming litholohic traps.These fans bear great significance to the exploration of lithologic reservoirs in the region.

Key words: Bouma sequence, turbidite deposits, geophysical response, sublacustrine fan, Lower Urho Formation, Permian, Karamay oilfield, Junggar Basin

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