Lattice Boltzmann Simulation Of Miscible Fluids Displacement

Study of miscible fluids displacement has significant value for scientific research and practical engineering, especially for CO2underground sequestration or storage and CO2resource utilization including enhanced oil recovery. In porous medium, the miscible displacement is a flow dynamic issue containing multiphase and multicomponents flow and complex geometrical channel. Many factors, such as fluids’physical property, pore structure and wettiablity, have effect on it. Understanding of its mechanism has not gotten completely until now. In hence, research of miscible displacement has important academic and applied sense. In this paper, we establish an improved lattice Boltzmann model for multicomponents flow. Moreover, we simulate and compare the case conducted in experiment, which proves our model’s feasibility. Besides, we carefully study the effect placed by vital factors on the miscible displacement in a channel. At last, we come up with the concept of geometrical characteristic unit and consider their impact on the displacement. Specific details as follows:(1) The improved lattice Boltzmann model for multicomponents flow is based on the two-fluid model. By considering every component’s influence on the main stream, describing the wall’s wettability through introducing potential function, and improve the disposal method of diffusion coefficient, the model is well in accord with the realistic physical problem.(2) We employ the improved lattice Boltzmann model to simulation free diffusion in a close tube and supercritical carbon dioxide displacing decane in channel. Through comparison diagram between simulation and experiment, the improved lattice Boltzmann model has evidences to confirm its feasibility and validity.(3) This paper defines characteristic quantities which can describe the miscible displacement. And through considering these quantities’ change with time or along the channel range, we study the impact of Reynolds number Re, Peclect number Pe, viscosity ratio R and wettability.(4) At last, we come up with geometrical characteristic unit, which includes dead end, backflow and bifurcate duct, to try to study the porous medium’s influence. Furthermore, we study their impact on the miscible displacement using our model.