Simulation of liquid flow transport in nanoscale porous media using lattice Boltzmann method

Investigations of Water Transport in Shale Reservoir with Dual-Wettability by Using Monte Carlo Method

How liquids transport in the shale system has been the focus because of fracturing fluid loss. In this study, a single-nanopore model is established for liquid transport in shale while considering the slip effect and effective viscosity of confined fluids. Then, the fractal Monte Carlo (FMC) model is proposed to upscale the single-pore model into shale porous media. The effects of different transport mechanisms, shale wettability, and pore characteristic parameters on confined liquid flow in shale rock are investigated. Results show that FMC permeabilities are 2-3 orders of magnitude larger than intrinsic and slip-corrected permeabilities in organic matter. However, the slip effect and effective viscosity have little influence on water flow in inorganic matter. With the contact angle of organic pore (θom) increasing and contact angle of inorganic pore (θin) decreasing, the effective permeability of the whole shale matrix grows in number. The enhancement factor in the situation of θom = 170° and θin = 20° is 4 orders of magnitude larger than the case of θom = 130° and θin = 40°, although the close effective macroscopic contact angle (θeff = 80°) occurs in these two cases, which indicates that shale microscopic wettability has a significant impact on the confined liquid transport. Moreover, with the increase of porosity and maximum pore diameters, shale permeability increases rapidly, but the enhancement factor has the opposite trend. Compared with the tiny impact of the variance of minimum inorganic pore diameters, minimum organic pore diameters have more significant impacts on liquid flow in shale systems, and the enhancement factor also rapidly increases up to 30 times for the case of 0.5 nm because of the strong slip effect.

A simulation study on hydrogel performance for enhanced oil recovery using phase-field method

Hydrogels are increasingly applied in oil recovery processes. This leads to more controlled flow of fluids in porous media. In this process, hydrogel is injected to the reservoir to block the high permeability areas. The trapped oil in low permeability regions, is then swept by water flooding. pH‐sensitive hydrogel microspheres were synthesized in another work of the authors, which effectively increased the oil recovery factor in experimental studies. In this communication, phase-field approach was used to simulate this process and to obtain the tuning parameters of the model including thickness of the contact surface (є), phase transform parameter (M₀), and excess free energy (∧). Diffusion of hydrogels was studied by Cahn–Hilliard conservative approach and the breakage, deformation, and plugging mechanisms were analyzed, based on pressure drop variations in micromodel. Moreover, Effective parameters on oil recovery factor were analyzed. Results indicated a good agreement between experimental and modeling studies of oil recovery factor in water and hydrogel flooding with absolute errors of 2.29% and 4.06%, respectively. The recovery factor was calculated using a statistical method which was in good agreement with the modeling results. The tuned parameters of the model were reported as, є = 111.7 µm, M₀ = 5 × 10⁻¹³ m³/s, \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\wedge = - 0.0003$$\end{document}∧=-0.0003 J/m³.