裸眼系列完井方式下叠式分支水平井产能预测

A Productivity Forecasting Method for Stacked Multilateral Horizontal Well under Open Hole Series Completion System

综合运用保角变换、镜像反映原理、势的叠加原理以及等值渗流阻力等数学和渗流力学分析方法,推导出裸眼系列完井方式下叠式分支水平井的产能解析公式,当分支数目为1时,所推导的解析公式退化为著名的Borisov公式。分析了影响其产能的几个重要因素,从而为该类型分支井的完井方案设计提供参考依据。经研究发现,完井筛管挡砂精度越高,相比水平井,叠式分支水平井产能损失相对越少;叠式分支水平井的产能受其在上下封闭边界油藏中垂向位置的影响较小;相比微元段模型,解析模型预测的产能偏高,引入校正系数后可减小偏差。

A series of productivity forecasting formulas for stacked multilateral horizontal well under open hole series completion system have been derived.Many relative mathematical analytical methods and permeation fluid mechanics are used,i.e.conformal transformation,potential superposition theory,method of mirror and equivalent filtrational resistance theory.The formula for ideal well can be simplified as the Borisov Equation when there is only one branch.The study found that stacked multilateral horizontal well will take a relatively less productivity reduction than traditional horizontal well in the case of a higher sieve-opening sine of premium screen pipe for sand control.Productivity of this type of well is almost free from its vertical location in closed boundary reservoir.A coefficient has been adopted to correct the productivity overestimated by the analytical method after comparing with infinitesimal method.