Unlike conventional reservoirs where pore size distribution has a micrometer scale (Nelson 2009), tight oil and shale gas reservoirs have predominantly mesopores (between 2 and 50 nm) and micropores (below 2 nm). Volume fraction of micropores is not negligible and can be as high as 20% (Kuila et Prasad 2011). As hydrocarbon molecules range between 0.5 and 10 nm (Nelson 2009), interaction...
Natural gas production from shale formations has received extensive attention in recent years. While great progress has been made in understanding the adsorption and transport of single-component gas (usually CH$_4$) inside shales’ nanopores, the adsorption and transport of multicomponent shale gas under more realistic reservoir conditions (e.g., considering CH$_4$/C$_2$H$_6$ mixture) only...
Abstract
Understanding the gas occurrence states under real reservoir conditions is the prerequisite to study the mechanisms of gas flow in shale reservoirs, in which large amounts of nanoscale organic pores exist. Besides, water is inevitable when considering the gas flow in shales. Thus molecular dynamics simulations were performed to study the occurrence states of gas-water mixtures...
Gas production from unconventional source rocks, such as ultra-tight shales, has increased significantly over the past decade. However, due to the extremely small pores (~ 1-100 nm) and the strong material heterogeneity, gas transport in shale is still not well understood which poses challenges for predictive field-scale simulations. In recent years, digital rock analysis has been applied to...
A novel approach is suggested to simulate the gas mixture transport in slit nanopores. The proposed method is based on the modification of the dual control volume grand canonical molecular dynamics (DCV-GCMD) method. The conventional method, DCV-GCMD, describes the gas mixture transport with pre-set constant composition. Due to the selective adsorption in the nanopores, the composition of the...
A series of canister desorption tests were carried out on 31 deep (over 3000 m) over-mature Lower Permian-Upper Carboniferous shale cores under atmospheric pressure and at reservoir temperatures of 75 and 80 °C, as well as a higher temperature of 95°C. Organic chemistry and X-ray diffraction were combined to investigate the impact of composition on canister desorption behavior. In order to...
Shale gas has redefined energy landscape[1]. The United States (U.S.) natural gas production is expected to increase every year, and in 2035 the U.S. shale gas production may raise to 50% of the total gas production.
Shale rock consists of micropores and mesopores[2]. It is also composed of inorganic minerals (quartz, clays, calcites, and feldspars, etc.) and organic matter (kerogens and...
