Special Oil & Gas Reservoirs ›› 2023, Vol. 30 ›› Issue (1): 29-35.DOI: 10.3969/j.issn.1006-6535.2023.01.004

• Geologic Exploration • Previous Articles     Next Articles

Study on the Exploration Method of Shale Gas in Permian Gufeng Formation, Xuancheng Area, Lower Yangtze Block

Zhang Xu1,2, Gui Herong2, Hong Dajun1, Sun Yankun3,4, Liu Hong1, Xiao Wanfeng1, Chen Kefu1, Yang Zhicheng1   

  1. 1. Geological Exploration Technology Institute of Anhui Province (Energy Exploration Center of Bureau of Geology and Mineral Exploration of Anhui Province), Hefei, Anhui 230041, China;
    2. National Engineering Research Center of Coal Mine Water Hazard Controlling(Suzhou University), Suzhou, Anhui 234000, China;
    3. Key Laboratory of Tectonics and Petroleum Resources Ministry of Education, China University of Geosciences (Wuhan), Wuhan Hubei 430074, China;
    4. Key Laboratory of Theory and Technology of Petroleum Exploration and Development in Hubei Province, China University of Geosciences (Wuhan), Wuhan Hubei 430074, China
  • Received:2022-03-29 Revised:2022-09-22 Online:2023-02-25 Published:2023-03-24

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Abstract: In view of great difficulties in the exploration of Permian shale gas under complex geological conditions in Xuancheng Area, Lower Yangtze Block, an effective shale gas exploration method under complex geological conditions is explored by applying a joint exploration with high-accuracy gravity prospecting, high-precision magnetic method and complex resistivity method (CR method) based on rock property testing. The study shows that The shale of Gufeng Formation in Xuancheng Area is characterized by "low magnetic intensity, low density, medium low resistivity and high polarization", the carbonaceous siliceous shale characterized by low resistivity and high polarization, and the intrusive rock (granite porphyry) that mainly affects Gufeng Formation characterized by "low magnetic intensity, low density, low resistivity and low polarization". In the shale gas exploration at Gufeng Formation, Weidun Belt, Xuancheng Area, high-accuracy gravity prospecting and high-precision magnetic method are applied to identify the areas with low magnetic intensity and low gravity and to deduce the distribution of rock mass. Then, CR profile is arranged in the area where magmatic rock is not developed, and wells are drilled for verification at the locations with low resistivity (less than 1 000.00 Ω·m) and high polarisation (more than 4.00%). A total of 50.89 m thick carbonaceous siliceous shale and siliceous mudstone of Gufeng Formation are drilled, achieving excellent application effect. This study provides an important guide to the identification of organic-rich shale formations and the selection of shale gas "sweet spot" in Xuancheng Area and even in the area with complex geological conditions in Lower Yangtze Block.

Key words: polarization rate, organic-rich shale, magmatic rocks, Xuancheng Area

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