Extremely low permeability due to nano-scale pores is a distinctive feature of gas transport in a shale matrix. The permeability of shale depends on pore pressure, porosity, pore throat size and gas type. The pore network model is a practical way to explain the macro flow behavior of porous media from a microscopic point of view. In this research, gas flow in a shale matrix is simulated using a...

[1] We report on laboratory experiments designed to investigate the influence of pore pressure oscillations on the effective permeability of fractured rock. Berea sandstone samples were fractured in situ under triaxial stresses of tens of megapascals, and deionized water was forced through the incipient fracture under conditions of steady and oscillating pore pressure. We find that short‐term p...

MATCHED asymptotic expansions are used to examine the stress and pore pressure fields near the tip of a plane strain shear (mode II) crack propagating on an impermeable plane in a linear elastic diffusive solid. For propagation speeds V that are large compared with c/I, where c is the diffusivity and I is the cracklength, boundary layers are required at the crack-tip and on the line ahead of th...

The standard model of injection-induced seismicity considers changes in Coulomb strength due solely to changes in pore pressure. We consider two additional effects: full poroelastic coupling of stress and pore pressure, and time-dependent earthquake nucleation. We model stress and pore pressure due to specified injection rate in a homogeneous, poroelastic medium. Stress and pore pressure are us...

Understanding the adsorption mechanisms of CO2 and N2 in illite, one of the main components of clay in shale, is important to improve the precision of the shale gas exploration and development. We investigated the adsorption mechanisms of CO2 and N2 in K-illite with varying pore sizes at the temperature of 333, 363 and 393 K over a broad range of pressures up to 30 MPa using the grand canonical...

X-ray microtomography was used to image the shape and size of residual ganglia of supercritical CO2 at resolutions of 3.5 and 2 lm and at representative subsurface conditions of temperature and pressure. The capillary pressure for each ganglion was found by measuring the curvature of the CO2-brine interface, while the pore structure was parameterized using distance maps of the pore space. The f...

Toward elucidating how a wavy porous sand bed perturbs a turbulent flow above its surface, we record pressure within a permeable material resembling the region just below desert ripples, contrasting these delicate measurements with earlier studies on similar impermeable surfaces. We run separate tests in a wind tunnel on two sinusoidal porous ripples with aspect ratio of half crest-to-trough am...

Fig. 1. Behavior of condensates on smooth surfaces and within pores. The surface wettability determines the contact angle θ and the curvature of a liquid condensate on a smooth surface (A) and within a pore (B), where θ and the pore diameter strongly affect the liquid’s vapor pressure (C), here for the case of liquid water. Capillary condensation of a liquid (red) and subsequent crystal (green)...

In this work, the local pressure of fluids confined inside nanoslit pores is predicted within the framework of the density functional theory. The Euler-Lagrange equation in the density functional theory of statistical mechanics is used to obtain the force balance equation which leads to a general equation to predict the local normal component of the pressure tensor. Our approach yields a genera...

The study of pore level displacement of immiscible fluids has scientific appeal as well as many applications, notably in oil reservoir engineering and in subsurface environmental engineering. Pore network models have been used for numerical simulation of fluid displacement over relevant physical volume sizes. An accurate description of the mechanics of displacement could significantly improve t...