China Petroleum Exploration ›› 2019, Vol. 24 ›› Issue (1): 82-94.DOI: 10.3969/j.issn.1672-7703.2019.01.009

• PETROLEUM GEOLOGY • Previous Articles     Next Articles

Characteristics and distribution of karst reservoirs in the Leikoupo Formation, western Sichuan Basin

Bian Congsheng, Wang Zecheng, Jiang Qingchun, Chi Yingliu, Xu Zhaohui   

  1. PetroChina Research Institute of Petroleum Exploration & Development
  • Received:2018-06-26 Revised:2018-10-14 Online:2019-01-15 Published:2019-01-02
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Abstract: The Leikoupo Formation in the Sichuan Basin developed carbonate platform deposits represented by shoal dolomite and karst reservoirs. Important discoveries have been made in the western Sichuan Basin, such as the Zhongba gas field and the Xinchang gas field, it is the important target for Triassic gas exploration in the Sichuan Basin. Researches have been carried out to clarify the boundary between the Leikoupo Formation and the overlying Ma'antang Formation and the characteristics and distribution of the karst reservoirs in the Leikoupo Formation in the western Sichuan Basin. The results found 4 types of contacts. According to the outcrops, cores, thin slices, logging and seismic data, the boundary between Leikoupo Formation and Ma'antang Formation is redefined:Leikoupo Formation developed weathering crust and karst reservoirs which indicate an exposed environment. While Ma'antang Formation developed deep water deposits without dolomite and exposed top. Controlled by the exposed top and the paleogeomorphology, well-seismic data predict that good reservoirs are distributed in the central and southern parts of western Sichuan Basin, with strong heterogeneity and changing facies. Future exploration targets are proposed in the southern part of the western Sichuan Basin with the relation between the sources and the reservoirs.

 

Key words: Sichuan Basin, Leikoupo Formation, Ma'antang Formation, Identification mark, Karst reservoir

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