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为了得到一种评价水平气井工作效率和储层参数的方法,讨论了圆形封闭地层三维不稳态情形的水平气井产能动态.通过引入拟压力,拟时间函数,利用Duhamel褶积和数值反演得到了水平气井McCray型产量积分平均递减图版及导数图版,结合实例给出了图版拟合的步骤和方法.结果表明:McCray型产量积分平均递减可以分为两个阶段,第1阶段为不稳态递减阶段,其递减曲线发散,第2阶段为拟稳态递减阶段,其递减曲线归一,与Arps调和递减曲线吻合.生产实例显示:理论图版与实际数据点的拟合率相对误差在1%～2%之间,符合工程精度要求,利用该方法可以预测储层有效渗透率、泄流面积、泄流孔隙体积、等效泄流半径、储层表皮因子、初始递减产量以及初始递减率等参数.
In order to get a method to evaluate the working efficiency and reservoir parameters of horizontal well, the productivity of horizontal well with three-dimensional instability in circular closed formation is discussed. By introducing pseudo-pressure and quasi-time function, Duhamel convolution and numerical inversion The mean integral decreasing plot and derivative plot of McCray type yield gas horizontal well were obtained, and the steps and methods of plate fitting were given in combination with the examples.The results showed that the average decrement of McCray type yield integral could be divided into two phases, the first phase was unstable The second step is the quasi-steady-state decreasing phase, and its decreasing curve is normalized, which is in agreement with Arps harmonic decreasing curve.Production example shows that the relative error between fitting rate of the theoretical plate and the actual data point is between 1 % ~ 2%, in line with engineering accuracy requirements, the use of the method can predict effective reservoir permeability, discharge area, discharge pore volume, equivalent discharge radius, reservoir skin factor, the initial decline in production and the initial decline rate Other parameters.