Numerical simulation of displacement characteristics of CO2 injected in pore-scale porous media

Abstract

Pore structure of porous media, including pore size and topology, is rather complex. In immiscible two-phase displacement process, the capillary force affected by pore size dominates the two-phase flow in the porous media, affecting displacement results. Direct observation of the flow patterns in the porous media is difficult, and therefore knowledge about the two-phase displacement flow is insufficient. In this paper, a two-dimensional (2D) pore structure was extracted from a sandstone sample, and the flow process that CO2 displaces resident brine in the extracted pore structure was simulated using the Navier-Stokes equation combined with the conservative level set method. The simulation results reveal that the pore throat is a crucial factor for determining CO2 displacement process in the porous media. The two-phase meniscuses in each pore throat were in a self-adjusting process. In the displacement process, CO2 preferentially broke through the maximum pore throat. Before breaking through the maximum pore throat, the pressure of CO2 continually increased, and the curvature and position of two-phase interfaces in the other pore throats adjusted accordingly. Once the maximum pore throat was broken through by the CO2, the capillary force in the other pore throats released accordingly; subsequently, the interfaces withdrew under the effect of capillary fore, preparing for breaking through the next pore throat. Therefore, the two-phase displacement in CO2 injection is accompanied by the breaking through and adjusting of the two-phase interfaces.

Interfacial tension and contact angle in CO2‐water/nanofluid‐quartz system

“…The capillary pressure does not scale with the IFT because of this wettability change . In the studies of CO 2 invasion into porous media, the effect of IFT is considered important; however, the effect of CA is overlooked . The IFT values combined with CA are important for the measurement of relative permeability and the water retention curve …”

“…[44][45][46][47] In the studies of CO 2 invasion into porous media, the effect of IFT is considered important; however, the effect of CA is overlooked. 48,49 The IFT values combined with CA are important for the measurement of relative permeability and the water retention curve. [50][51][52][53] The surface de-wetting phenomenon by CO 2 has been reported in the literature.…”

Reservoir Permeability Evolution during the Process of CO2-Enhanced Coalbed Methane Recovery

“…Coalbed methane (CBM) recovery from coal seams, as an unconventional resource, is a growing contributor to the energy supply for the energy-hungry world [1][2][3]. Carbon dioxide (CO 2 ) geological storage through reducing the risk of CO 2 migration to the surface is becoming an important method for effective control of greenhouse gas [4][5][6][7]. CO 2 -enhanced coalbed methane (CO 2 -ECBM) recovery is a technology that increases CBM production while controlling greenhouse gas by injecting CO 2 into CBM reservoirs, which has already been applied in several field projects [8][9][10].…”

Identifying attributes of CO2 leakage zones in shallow aquifers using a parametric level set method

“…[22][23][24] This capability for tracking topological changes has also made the level set method appealing for solving many types of inverse problems, such as those arising in medical tomography, shape reconstruction, and structural topology optimization. [22][23][24] This capability for tracking topological changes has also made the level set method appealing for solving many types of inverse problems, such as those arising in medical tomography, shape reconstruction, and structural topology optimization.…”

“…The original level set method, first introduced by Osher and Sethian, 21 has been widely used for tracking the motion of fluid fronts and interfaces in multiphase flow simulations, including the movement of supercritical CO 2 plume in brine formations at pore and continuum scales. [22][23][24] This capability for tracking topological changes has also made the level set method appealing for solving many types of inverse problems, such as those arising in medical tomography, shape reconstruction, and structural topology optimization. 25,26 In those applications, level set methods are used to control the smoothness of shape boundaries, which is essential for avoiding the slow convergence of topology optimization process.…”