阶梯水平井产能预测方法

Deliverability prediction for stepped horizontal wells

根据质量守恒原理和动量守恒原理,建立了双台阶水平井筒沿程压降模型。通过比产能指数将井筒中的流动与油藏渗流进行了耦合。模型中油藏渗流计算采用JOSHI稳态流动模型,水平井筒摩擦压降计算考虑了壁面流入的影响。并为所建的模型编制了程序,通过实例计算分析双台阶水平井相关参数对产能的影响,认为对于大井眼、小产能水平井加速度压降可忽略,摩擦压降较小,由水平倾角引起的重力压降对产能有较大影响。本文为油藏工程分析和采油工艺分析建立了一种简单、快捷、有效的阶梯水平井产能预测方法。

Based on the principle of the mass conservation law and the momentum conservation principle, we estab- lished a mathematic model of drawdown along the horizontal wellbore and coupled the in-flow in the wellbore with seepage flow in the reservoirs by using specific productivity index. Reservoir filtration calculation in the model is expressed by the steady-state flow model of JOSHI, and calculation of frictional drawdown in wellbore takes into account the impact of the radial inflow. We also wrote program for the mathematic model, so as to calculate and analysis the effect of relevant parameters of the well upon its deliverability. The resuhs show that acceleration drawdown is negligible and frictional pressure-drop is insignificant in bigger borehole with lower deliverability, while that gravitational drawdown caused by inclination of wellbores has a bigger impact upon the deliverability. The article provides a simple,easy and effective way for predicting the deliverability of steeped horizontal wells.