元坝气井射孔完井近井壁渗流场分析

Analysis of the Fluid Flow Field Near Wellbore Wall of Gas-well Perforated Completion in Yuanba

川东元坝地区主要为超深水平井气井,超深井井底高温、高压下,近井壁天然气的密度、黏度和压缩系数随压力的变化而变化,是一个复杂的流场问题,很难用解析解研究射孔完井近井壁的渗流场问题,用COMSOL Multiphysics多物理场软件建立了元坝气井射孔完井近井壁渗流场分析的三维有限元模型,模型中包含了井眼尺寸、孔深、孔径、孔密、相位角、钻井污染程度、渗透率、流体密度、黏度以及压缩系数等,可以方便地调整任意参数,得到相应的近井筒渗流场的分布规律。根据建立的渗流场有限元模型,详细分析了不同相位角、不同孔密时,近井筒渗流场的相互干扰情况,为水平井气井射孔完井参数优化设计提供了理论依据。

The wells in Chuandong Yuanba are mainly extra-depth horizontal gas wells. Because the density, viscosity and compressibility coefficient of nature gas vary with the temperature and pressure, the problems of the fluid flow field near wellbore wall of the gas-well perforated completion are not solved with the analytical method. In the paper, the 3D fluid flow finite element model （FEM） near the wellbore wall is established with the COMSOL Multiphysics software. The model includes the wellbore size, perforation depth, perforation diameter, perforation density, phasing angle, drilling damage degree, permeability, gas density, viscosity as well as compressibility coefficient, and so on. We can change the arbitrary parameter to get the distribution of the fluid flow field near the wellbore wall. Based on the fluid flow model in the paper, the reciprocal interference near wellbore fluid flow field under the different phasing angles and different perforation density was analyzed in details. It provides the theoretical supports for the optimal design of the perforated completion parameters in horizontal gas well.