论文部分内容阅读
在压裂气井中，低粘气体在高导流支撑裂缝中的渗流阻力降低，渗流速度加快，气体渗流入井的流动由达西流变为非达西流。目前基于达西流动假设所制作的预测压裂井生产动态的典型图版，对压裂气井生产动态的计算结果与实际相差较大。为此在引入非达西因子的基础上，首次推导建立了压裂气井中真实气体在地层—裂缝中非达西渗流的数学模型，采用有限差分法得到了该模型的数值方程和求解方法，推导了非达西因子的数值计算法，模拟计算了压裂气井生产过程中的非达西因子和井底、地层及支撑裂缝中的压力动态。计算表明压裂气井中存在的非达西渗流对压力动态和生产动态有显著影响，在低导流能力、高产压裂气井中非达西流的影响更为显著。文中的模型和方法可应用于气井压裂后动态预测和气藏整体压裂数值模拟。
In frac gas wells, the seepage resistance of low viscous gas in high-conductivity support fractures is reduced, the seepage velocity is accelerated, and the flow of gas infiltration into the well is changed from Darcy flow to non-Darcy flow. At present, based on the Darcy flow assumptions produced by the production of a typical fracturing plate plot, the production of fracturing gas wells dynamic calculation results and the actual difference. Therefore, based on the introduction of non-Darcy factor, the mathematical model of true Darcy flow in fissured gas wells in fissure gas wells was deduced for the first time. The numerical equation and its solution method were obtained by finite difference method. The numerical calculation method of non-Darcy factor is deduced. The non-Darcy factor and the pressure dynamic in the bottom hole, formation and supporting cracks in the fracturing gas well are simulated and calculated. Computation shows that the non-Darcy flow existing in the frac gas well has a significant effect on the pressure dynamic and the production dynamic. The influence of non-Darcy flow in the low conductivity and high-pressure fractured gas wells is more significant. The model and method in this paper can be applied to the dynamic prediction after gas well fracturing and the numerical simulation of gas fracturing.