ZHANG Ming-yang, LI Xian-qing*, DONG Ze-liang, GUO Man, SUN Meng-meng, FAN Jian-ping
State Key Laboratory of Coal Resources and Safe Mining, College of Geoscience grad Surveying Engineering, China University of Mining and Technology(Beijing), Beijing 100083, China

Abstract: In order to study the mineral compositions of the lower Cambrian Hetang Formation shale and the physical properties of shale gas reservoirs in South Anhui, the X-ray diffraction (XRD) and organic geochemical analyses were conducted in this paper. The characteristics of organic matter, mineral contents and brittleness of the Hetang Formation shale in South Anhui were discussed. The results showed that the organic carbon content of the Hetang Formation shale in South Anhui is relatively high (mainly 1.0%~10.0%), the organic matter are mainly type I organic matter and had undergone an over-mature thermal evolution (Rom=4.2%~5.3%). The Hetang Formation shale has a complicated mineral composition, the major components are quartz, clays and carbonate mineral whose average contents are 68.2%, 24.5% and 3.3%, respectively, while small amount of feldspar, dolomite, siderite, pyrite and gypsum were also found in some samples. The Hetang Formation shale in South Anhui has a higher brittle mineral content (average 73.9%), and bigger brittleness index value (average 71.7%) in compared with those of North American. It is suggested that the Hetang Formation shale in South Anhui has good brittleness and is favorable to forming fracturing formation for shale gas.

Keywords: shale gas Hetang formation shale mineral composition brittleness southern Anhui

*Corresponding Author, E-Mail: Lixq@cumtb.edu.cn

Bulletin of Mineralogy, Petrology and Geochemistry Vol. 34, No.1, 2015, page 177-183