Organic matter/clay mineral intergranular pores in the Lower Cambrian Lujiaping Shale in the north-eastern part of the upper Yangtze area, China: A possible microscopic mechanism for gas preservation

Composition and pore characteristics of black shales from the Ediacaran Lantian Formation in the Yangtze Block, South China

“…The range of EVRo values obtained from the Raman spectra analysis was slightly lower (3.97e4.12%). It is Han et al, 2013;Jiao et al, 2014;Liang et al, 2014;Tang et al, 2015;Tian et al, 2013Tian et al, , 2015Wang et al, 2014), and EVRo values higher than 4% have also been reported for Lower Cambrian shales from the Yangtze Block (Ma et al, 2015;Wang et al, 2015). The Lantian shales are thus an additional reference for the compositional and pore characteristics of ultrahigh maturity shales.…”

“…Reported porosities for over-mature marine shales from the Yangtze Block range mainly between 0.4% and 9.7% (Jiao et al, 2014;Liang et al, 2014;Ma et al, 2015;Tian et al, 2013Tian et al, , 2015Wang et al, 2014), and many samples have been reported to have higher porosity values (e.g., 10e15%, Cao et al, 2015;Chen et al, 2011;Tan et al, 2014a; 3. TS (total sulfur) content of shales determined directly by the element analyser vs. that calculated from XRD analysis pyrite content.…”

“…The XRD analysis in this work has indicated a generally high pyrite content, up to 19%, except in one siltstone sample with extremely low TOC content (0.18%, Table 1). Mineralogical studies have shown pyrite content with a range for the majority of samples from 1% to 9% for Neoproterozoic, Lower Cambrian and Lower Silurian marine shales from the Upper Yangtze Block (Cao et al, 2015;Hou et al, 2014;Jiao et al, 2014;Liang et al, 2014;Ma et al, 2015;Tang et al, 2015;Tian et al, 2013Tian et al, , 2015Wang et al, 2013Wang et al, , 2014Wu et al, 2014), and highly abundant pyrite (ca. 12%) was observed in only a few samples (Han et al, 2013;Tan et al, 2014a).…”

“…These are some of the most promising strata for shale gas exploration in China (Dong et al, 2014;Tan et al, 2014aTan et al, , 2014bZou et al, 2011). Stratigraphic studies have indicated that the black shales in the Ediacaran Doushantuo Formation were mainly deposited in deep-water slope and basin settings (Jiang et al, 2011;Zhu et al, 2007); however, unlike the Cambrian and Silurian shales Han et al, 2013;Jiao et al, 2014;Liang et al, 2014;Ma et al, 2015;Tang et al, 2015;Tian et al, 2013Tian et al, , 2015Wang et al, 2015), the Ediacaran shales have not been described in great detail (Tan et al, 2014a).…”

Vertical Heterogeneity of the Shale Reservoir in the Lower Silurian Longmaxi Formation: Analogy between the Southeastern and Northeastern Sichuan Basin, SW China

“…The Chengkou-Fangxian Fault is a typical example of the tectonics in this region. It divides the Dabashan arc-like thrust fold belt into the northern-and southern-Dabashan regions ( Figure 1) [24,25]. The study area is located in the southern Dabashan region (Figure 1).…”