Oil & Gas Geology ›› 2015, Vol. 36 ›› Issue (1): 118-127.doi: 10.11743/ogg20150115

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Sedimentary characteristics of shallow-water delta distributary channel sand bodies: a case from Ⅱ-Ⅰ Formation of Fuyu oil layer in the Sanzhao Depression, Songliao Basin

Deng Qingjie1,2, Hu Mingyi1,2, Hu Zhonggui1,2, Wu Yukun3   

  1. 1. Key Laboratory of Exploration Technologies for Oil-Gas Resource of Ministry of Education, Yangtze University, Wuhan, Hubei 430100, China;
    2. School of Geosciences, Yangtze University, Wuhan, Hubei 430100, China;
    3. Zhanjiang Branch, CNOOC China Ltd., Zhanjiang, Guangdong 524057, China
  • Received:2014-08-06 Revised:2014-12-02 Online:2015-02-08 Published:2015-02-11
  • Contact: 胡明毅(1965-), 男, 教授、博士生导师, 沉积学与层序地层学.E-mail:humingyi65@163.com E-mail:humingyi65@163.com

Abstract:

Subtle lithologic reservoirs with shallow burial depth in the Ⅱ-Ⅰ Fms of Fuyu oil layers (FⅡ-FⅠ) are widely distributed in Sanzhao Depression, Songliao Basin, and are the major targets of tight oil exploration for reserve growth.The FⅡ-FⅠ in Sanzhao Depression are dominated by shallow water delta depositional systems featuring in complex change of sedimentary facies belt, and their main reservoir frameworks consist of distributary channel sandbodies.Based on detailed core observation of 53 wells and combining with logging data of more than 1 000 wells, 11 types of lithofacies were recognized in the distributary channel sandbodies of FⅡ-FⅠ in study area, and they were grouped into 3 lithofacies associations according to different datum level cycles.There are three types of interlayers in single distributary channel, including muddy interlayer, calcareous interlayer and conglomeratic siltstone, by which the internal architecture configuration of single distributary channel sand body was further analyzed.Comparison models for cotemporaneous channel sandbodies and interlayers were built through flattening of the tops of distributary channel sandbodies and were used to compare the sandbodies in respects of lithology, types of interlayer and shapes of logging curve.Methods were proposed for identifying the interwell cotemporaneous channel sandbodies between wells with small spacing within the sequence stratigraphic framework and the distribution of sandbodies was also discussed.Based on the comparative method above, combining with comparison of sandbodies by fence diagram and seismic attribute analysis, the distribution characteristics of single distributary channel sandbody were described, providing a geologic foundation for tight oil exploration and development.

Key words: single distributary channel sandbody, type of interlayers, architecture configuration, Ⅱ-Ⅰ Formation of Fuyu oil layer, Sanzhao Depression, Song liao Basin

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