Oil & Gas Geology ›› 2014, Vol. 35 ›› Issue (2): 272-279.

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Shale gas accumulation conditions of the Lower Cambrian Niutitang Formation in Upper Yangtze region

Hu Mingyi1,2, Deng Qingjie1,2, Hu Zhonggui1,2   

  1. 1. Key Laboratory of Exploration Technologies for Oil and Gas Resources of Education, Yangtze University, Wuhan, Hubei 430100, China;
    2. Faculty of Earth Sciences, Yangtze University, Wuhan, Hubei 430100, China
  • Received:2013-11-20 Revised:2014-02-20 Online:2014-04-08 Published:2014-05-21

Abstract: Based on outcrops,drilling and core data,combining with analysis of thin section,SEM,X-ray diffraction,mercury porosimetry and isothermal adsorption,this paper studied the accumulation conditions and characteristics of shale gas of the Lower Cambrian Niutitang Formation in Upper Yangtze Region,with focus on the stratigraphic,petrologic,geoche-mical and geophysical characteristics as well as gas storage capacity.The results show that the distribution of the organic-rich shale of the Lower Cambrian Niutitang Formation in Upper Yangtze Region is controlled by the shallow to deep water shelf sedimentary environment,where shale thickness generally ranges from 50 to 300 m.The shale has a total organic carbon content over 1.5% and is highly mature to over mature.The organic-rich shale has abundant brittle minerals and the clay minerals with high evolution are dominated by stable minerals such as illite but without any montmorillonite.The various types of pores and fractures provide effective reservoir space for shale gas,and the gas content reaches the lowest commercial development value(2.0 m3/t).Comprehensive analysis of these conditions reveals that the Ziyang-Zigong area,the northern Guizhou,eastsouthern Chongqing and eastern Hubei and Hunan Province are favorable exploration areas.

Key words: organic-rich shale, accumulation condition, favorable exploration area, Niutitang Formation, Upper Yangtze region

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