微粒沉积导致孔喉尺寸变化的Lattice Boltz-Mann模拟研究

LBM Simulation of Pore-Throat Radius Variation Due to Particle Deposition

油气田开发过程中,微粒在孔喉内的沉积会导致孔喉有效尺寸减小,流体流动能力降低。为研究微粒沉积对孔喉尺寸的影响及孔喉尺寸变化规律,以毛管模型为基础,通过理论推导和LBM模拟结合的方法对微粒沉积后孔喉有效半径进行求解,并选取不同参数进行了敏感性分析。模拟结果显示,随微粒粒径的增大,孔喉有效半径减小,且微粒越大有效半径减小越快;微粒沉积位置越靠近入口端,孔喉有效半径越小;孔喉长度与宽度比值越大时,孔喉有效半径值越大。最后通过回归建立了微粒沉积后孔喉有效半径的计算数学模型,可对从微观尺度研究微粒沉积导致储层伤害起到一定的指导作用。

During the developing process of oil and gas reservoirs, particles deposited in pore-throats may result in the decrease of its effective radius and capability for fluid flowing through. For studying the influence of deposited particles on the pore-throat radius and its changing rule, the formula for calculating the effective radius is obtained based on the capillary model and theoretical deri-vation. Besides, sensitive analysis is conducted for various parameters. The simulation results show that, the effective radius of pore-throats gets smaller with the increase of deposited particle radius and the decreasing rate is higher at the bigger particle size;the closer the particle deposits from the inlet face, the smaller of the effective radius is;besides, the effective radius of the pore- throat will be much greater when the pore-throat has a bigger ratio value between the length and its width. In addition, a mathematical model for calculating the effective radius is proposed based on the regression fitting, which may provide a useful guidance for research on the formation damage.