Breakthrough pressure and permeability in partially water-saturated shales using methane–carbon dioxide gas mixtures: An experimental study of Carboniferous shales from the eastern Qaidam Basin, China

Experimental Investigation on the Movability of Water in Shale Nanopores: A Case Study of Carboniferous Shale From the Qaidam Basin, China

“…Before commencing the water movability experiments, the shale samples were fully saturated. The apparatus used for the water saturation experiments and the corresponding experimental procedures are presented by Zhang and Yu (2019). Gas bubbles tend to block pore throats, hinder fluid flow, and thus reduce permeability (Dewhurst et al, 1998).…”

“…A detailed description of the measurement methodology is presented by Wang and Yu (2016). The specific surface area and porosity, which are the factors affecting the permeability of sedimentary rocks, were obtained from adsorption and mercury intrusion experiments (Schlomer & Krooss, 1997; Zhang & Yu, 2019). Considering that the samples are shale matrix and that a constant confining pressure of 15 MPa was applied, only pores with diameters less than 10 μm were analyzed.…”

“…The fluid injection system, controlled by a high-pressure constant-flow pump and back-pressure valve, provided a constant pressure to achieve steady state flow. The injection pressure was at least 5 MPa lower than the confining pressure to reduce the possibility of hydraulic fracturing within the shales and leakage of liquid from the gap between the rubber sleeve and the sample (Zhang & Yu, 2019). Additionally, the pipelines, containers, core holder, and measuring system were thermostatically controlled, excluding the syringe pump and constant-flow pump.…”

“…Due to their low porosity and permeability, shales are treated as host rocks of high‐level nuclear waste repositories and caprocks of carbon dioxide geological storage and petroleum reservoirs (Borysenko et al, 2009; Tsang et al, 2012; Zhang & Yu, 2016). In recent years, the exploration and development of shale gas have attracted increasing attention in many countries (Zhang & Yu, 2019), raising great interest in fundamental investigations on the effective porosity, permeability, and irreducible bound water of shale (Yuan et al, 2018). Thus, understanding the distribution and movement characteristics of water in shale nanopores is extremely important for the shale gas exploitation and environmental protection.…”

A Caprock Evaluation Methodology for Underground Gas Storage in a Deep Depleted Gas Reservoir: A Case Study for the X9 Lithologic Trap of Langgu Sag, Bohai Bay Basin, China

“…At present, the caprock evaluation of gas storage is mainly divided into two aspects: the macro-and the micro-effectiveness evaluation of caprock [5]. From the macro perspective, lithology, thickness, continuity, and brittle-ductile characteristic have a significant influence on the sealing capacity of caprock [6][7][8][9][10]. The physical sealing mechanism of the caprock means that the caprock realizes the function of gas sealing through its physical properties.…”