Shale lithofacies and reservoir space of the Wufeng–Longmaxi Formation, Sichuan Basin, China

A preliminary study on the pore characterization of Lower Silurian black shales in the Chuandong Thrust Fold Belt, southwestern China using low pressure N2 adsorption and FE-SEM methods

“…The Lower Silurian Longmaxi Formation has been recognized as an effective source rock within and around the Sichuan Basin (Zou et al, 2010;Zeng et al, 2012). The Longmaxi Formation consists of a lower section of black shales and silty shales in which graptolite fossils are abundant (Liang et al, 2012). Its middle and upper sections are dominated by greyish-green shales and sandy shales (Fig.…”

“…Its middle and upper sections are dominated by greyish-green shales and sandy shales (Fig. 2), indicating variation of depositional environment from deep shelf to shallow shelf (Liang et al, 2012). The thickness of the black shales varies from several tens of meters to more than one hundred meters with depositional centers in the southern and eastern parts of the Sichuan Basin as well as the Chuandong Thrust Fold Belt, but they are absent in the western-central part of the Sichuan Basin (Fig.…”

“…In China three sets of marine shales have developed in southern China, including the Lower Cambrian, Upper Ordovician to Lower Silurian and Upper Permian shales (Zou et al, 2010). Among them, the Lower Cambrian and Upper Ordovician to Lower Silurian shales within and around Sichuan Basin are believed to be the primary gas shale targets because of their widespread occurrence, high content of organic matter, favorable mineral composition and large thickness as indicated from analysis of many outcrops and a few core samples (Wang et al, 2009;Zou et al, 2010;Chen et al, 2011;Huang et al, 2012;Liang et al, 2012;Long et al, 2012;Sun et al, 2012). In this study, eight black shale core samples from the Lower Silurian Longmaxi Formation in the Chuandong Thrust Fold Belt were preliminarily investigated for pore characterization, including total porosity, surface area, pore type and pore size distribution.…”

Geological models of gas in place of the Longmaxi shale in Southeast Chongqing, South China

“…The geochemical characteristics, pore structure and reservoir physical properties of the Longmaxi shale in South China have been widely reported recently (Liang et al, 2012;Huang et al, 2012;Tian et al, 2013Tian et al, , 2015Wang et al, 2013a); however, there are only a few papers related to the isothermal methane adsorption of the Longmaxi shale (e.g., Wu et al, 2012;Shi et al, 2015). These adsorption experiments were designed based on shales with different TOC contents at a single temperature (e.g., 30 C or 60 C) and at a maximum pressure of 12e15 MPa.…”

Study of the relationship between fractures and highly productive shale gas zones, Longmaxi Formation, Jiaoshiba area in eastern Sichuan

“…Among these, the shale gas fields of the Jiaoshiba area in Fuling contribute an annual production of 5.0 9 10 9 m 3 (Guo 2016a, b;Wang 2017). Both the reservoir space and accumulation mechanisms of shale gas are complex (Liang et al 2012;Gale et al 2014;Deng et al 2015;Tenger et al 2017), and it is difficult to ascertain the key factor controlling shale gas accumulation (Guo and Zhang 2014;Jin et al 2016;Guo et al 2017). This comprehensive study considers that shale fractures are a key factor controlling shale gas accumulation and productivity.…”