Oil & Gas Geology ›› 2014, Vol. 35 ›› Issue (4): 511-516.doi: 10.11743/ogg20140410

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Fracture characteristics of ultra-deep reef-bank lithologic gas reservoirs in the Upper Permian Changxing Formation in Yuanba area, Northeastern Sichuan Basin

Fan Xiaojun1, Peng Jun2, Li Jixuan1, Chen Dan1, Li Feng1, Deng Jinhua1, Huang Yong1, Miao Zhiwei1   

  1. 1. Exploration Research Institute, Southern Branch of SINOPEC, Chengdu, Sichuan 610041, China;
    2. Yangtze University, Wuhan, Hubei 430100, China
  • Received:2013-04-11 Revised:2014-05-14 Online:2014-08-08 Published:2014-08-28

Abstract:

In order to understand the fracture characteristics of reef-bank reservoir in the Changxing Formation in Yuanba area,northeastern Sichuan Basin,this paper finely described the fractures of the Changxing Formation in many wells,and also studied the tectonic evolution,hydrocarbon generation,diagenesis and the porosity evolution.Vertically,the fractures are mainly distributed in the 2nd Member of Changxing Formation.While laterally,they show strong heterogeneity in distribution,with heterogeneity being different in different blocks.Fractures are relatively well developed on structural high.The fractures can be divided into 3 types and 11 subtypes developed mainly in 3 stages.We established the classification evaluation index system and the standard identification chart of typical fractures.The formation of fractures is mainly controlled by the tectonic evolution,burial and dissolution.The dynamic fracture-pore assemblages of the 2nd and 3rd stages are better than that of the 1st stage.These assemblages form effective storage space or reticular carrier systems and make a positive contribution to the reservoir property and productivity.The comprehensive analysis indicates that the Changxing Formation in the northwestern Yuanba area is favorable for enrichment of oil/gas.

Key words: reef-bank reservoir, fracture characteristics, Changxing Formation, Yuanba area

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