基于DPM模型的水平井水平段沥青质颗粒运移规律数值模拟研究

Numerical simulation of asphaltene particle transport in horizontal well horizontal section based on DPM model

针对沥青质颗粒在水平井井筒的沉积问题,本研究采用Fluent中的DPM模块追踪沥青质颗粒在油管中的运动轨迹,采用realizable k-e模型对尺寸为10~100μm的沥青质颗粒在水平井筒内壁的沉积进行了研究。分析了重力、Saffman力以及阻力作用下,黏度、颗粒尺寸以及流速对沥青质颗粒沉积速率的影响。CFD模拟结果表明:(1)层流阶段,沉积速率随着黏度的增大而减小,这主要是因为层流阶段,流体流动较平稳,使得管壁附近速度梯度减小,Saffman升力降低引起的,而在湍流阶段,当黏度从0.001 2 Pa·s增加至0.012 Pa·s时,沥青质沉积速率会缓慢增加;当黏度从0.012 Pa·s增加至0.053 Pa·s,沉积速率和沉积百分数会随之下降;(2)当颗粒直径为10~100μm时,沥青质颗粒沉积百分数和沉积速率会随着流速的增加而减小;(3)当速度为0.3~2 m/s时,沥青质颗粒沉积百分数和沉积速率随着颗粒直径的增大而增大。研究结果为水平井井筒中的沥青沉积行为指明了方向,认为合理控制井筒中流体速度、黏度和颗粒直径可作为去除井筒沥青质沉积的有效手段。

To study the problem of asphaltic particles deposition in horizontal wellbore, the DPM module in Fluent was used to track the particle movement in tubing.And the realizable k-e model was adopted to investigate the asphaltene aggregates with a size of 10~100 μm on the inner wall of tubing.The effects of particle size and velocity on the asphaltene particle deposition rate are analyzed when the gravity, saffman lift, and drag forces are exerted on the particles.CFD simulation results show:(1) The deposition rate decreases with the increase of viscosity in the laminar flow stage.This is mainly because in the laminar flow stage, the fluid flow is relatively stable and Saffman lift decreases.The asphaltene deposition rate increases slowly in the range from 0.001 2 Pa·s to 0.012 Pa·s;the deposition rate and percentage decrease when the viscosity increases from 0.012 Pa·s to 0.053 Pa·s in the turbulent stage.(2)The deposition percentage and deposition rate of asphaltene particles decrease with the increase of flow rate when the particle diameter is 10-100 μm.(3)When the velocity is 0.3-2 m/s, the percentage and deposition rate of asphaltene particles increase with the increase of particle diameter.The analysis shows that reasonable control of wellbore fluid velocity and particle diameter can be an effective means to reduce asphaltic deposition in wellbore.