The Reservoir Features of the Wufeng-Longmaxi Formation Black-Shale in Southern Sichuan Basin, Western China: A Case Study from the Qilong Section, Xishui Country

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

As one of the best source rocks (Yan et al., 2008,Wang et al., 2008, Liang et al., 2009), the Upper Ordovician Wufeng Formation -- Lower Silurian Longmaxi Formation black shale is generally thought as to be a potential reservoir for shale gas in the southern part of Sichuan basin (Zou et al., 2010, Liu et al., 2011., Liang et al., 2011, Wan et al., 2012). However, there are only few studies on the reservoir parameters (e.g., Chen et al., 2011; Ma et al., 2012). Based on the organic geochemistry, mineralogy and adsorbed gas experiment etc., we have conducted a systematic research on reservoir features of the black shale in the Qilong section, southern Sichuan basin. The black shale in Wufeng-Longmaxi formation is characterized with an effective thickness of >50m, average organic carbon content (TOC) of 3.81% and an average content of 54.94% for quartz mineral. There is a positive correlation between the TOC and the content of quartz mineral, and a negative correlation between the TOC and the content of clay . Furthermore, there are positive relationships between the average porosity (with 4.93%) and the contents of TOC, quartz mineral and clay, between the average content of adsorbed gas (with 1.80 cm³/g under 7.0 MPa) and the contents of TOC, quartz mineral. Thus, we suggest that there is a good gas exploration prospect in the black shale of the Wufeng-Longmaxi formation.

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