Simulation and visualization of the displacement between CO2 and formation fluids at pore-scale levels and its application to the recovery of shale gas

Abstract

This article reports recent developments and advances in the simulation of the CO 2 -formation fluid displacement behaviour at the pore scale of subsurface porous media. Roughly, there are three effective visualization approaches to detect and observe the CO 2 -formation fluid displacement mechanism at the micro-scale, namely, magnetic resonance imaging, X-ray computed tomography and fabricated micromodels, but they are not capable of investigating the displacement process at the nano-scale. Though a lab-on-chip approach for the direct visualization of the fluid flow behaviour in nanoscale channels has been developed using an advanced epi-fluorescence microscopy method combined with a nanofluidic chip, it is still a qualitative analysis method. The lattice Boltzmann method (LBM) can simulate the CO 2 displacement processes in a two-dimensional or three-dimensional (3D) pore structure, but until now, the CO 2 displacement mechanisms had not been thoroughly investigated and the 3D pore structure of real rock had not been directly taken into account in the simulation of the CO 2 displacement process. The status of research on the applications of CO 2 displacement to enhance shale gas recovery is also analyzed in this paper. The coupling of molecular dynamics and LBM in tandem is proposed to simulate the CO 2 -shale gas displacement process based on the 3D digital model of shale obtained from focused ion beams and scanning electron microscopy.

Shale Gas Nanofluid in the Curved Carbon Nanotube: A Molecular Dynamics Simulation Study

“…However, exploring the dynamic properties of methane within such small-scale nanopores presents a considerable challenge. − Molecular dynamics simulation (MD) has emerged as an effective tool, enabling access to the nanometer-scale dynamic behavior of methane in nanopores. ,,,− …”

“… 41 − 46 Molecular dynamics simulation (MD) has emerged as an effective tool, enabling access to the nanometer-scale dynamic behavior of methane in nanopores. 42 , 43 , 45 , 47 − 58 …”

Surrogate-Assisted Evolutionary Optimization of CO2-ESGR and Storage

“…Liu et al summarized the CO 2 -ESGR techniques including CO 2 fracturing technology, CO 2 injection-enhanced gas recovery, and CO 2 geological storage in depleted shale gas reservoirs. The CO 2 -ESGR is similar to CO 2 -enhanced coalbed methane recovery in that CO 2 /CH 4 competitive adsorption is an important mechanism for the displacement of CH 4 . , It is recognized that although the CO 2 injection can effectively accelerate the desorption rate of CH 4 , the actual production process depends largely on various geological and engineering factors, such as porosity, permeability, formation thickness, gas injection volume and time, fracture height, fracture half-length, and fracture conductivity. However, few studies have systematically scrutinized the effect of these engineering and operating parameters on the potential of the CO 2 -ESGR and storage in hydraulically fractured shale gas reservoirs.…”

Effects of π–π Stacking on Shale Gas Adsorption and Transport in Nanopores

“…The adsorption and transport properties of methane in nanopores are profoundly influenced by the characteristics of the pore surface, including π–π stacking structures and the stacking orientation. However, investigating the intricate details of methane behavior at such a small scale remains challenging. − MD simulations have emerged as a valuable tool for exploring the nanoscale behavior of methane molecules in the porous shale matrix. − …”