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The Features of Black Shale (Gas) in the Neoproterozoic Doushantuo Formation in Western Hubei

Ziquan Yong, Xuan Zhang, Shugen Liu, Bo Ran, Di Yang, Chao Luo, Shiyu Wang, and Yuehao Ye
State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Chengdu University of Technology, Chengdu, China

Based on the outcrop, geological, geochemical research, this paper presents the features of black shale in the Neoproterozoic Doushantuo Formation in western Hubei. The Doushantuo formation is deposited in the facies of tidal flat, shelf lagoon, shelf margin and slope (Jiang et al., 2011). However, the black shale deposited in shelf lagoon facies, occurs in section B and section D of the Doushantuo formation, with total organic carbon (TOC) of 2% and 5%, respectively. The difference in TOC is thought to be dominantly related with sedimentary environment, e.g. water power condition, ancient salinity and oxydic environment. Furthermore, according to the scanning electron microscopy (SEM) observation, we argued that types of pore in the black shale comprise intragranular pore in quartz and clay mineral, and organic-matter pore. The organic-matter pore of segment D is higher than that of segment B, however, the intragranular pore of segment B is lower than segment D. Moreover, The gas content in black shale is 2.64 (VL)/(cm3/g) in segment D, and is 2.35 (VL)/(cm3/g) in segment B. Thus, we suggest that there is a good quality of reservoir both in section B and section D in the Doushantuo formation. Of which the reservoir shows a positive correlation to the TOC, the content of quartz and clay, in particular the TOC.

AAPG Search and Discovery Article #90175©2013 AAPG Hedberg Conference, Beijing, China, April 21-24, 2013