用改进的有限差分法预测地面示功图

本文根据杆式抽油系统动力学模型,在建立了适合于多级抽油杆柱的一维粘滞阻力波动方程的基础上,给出了一种计算抽油杆柱任意位置处位移的差分格式。这种方法不仅适合子单级抽油杆柱,也适合任意交杆径和变杆材的多级抽油杆柱。该方法与Gibbs和schafer等人的预测模型不同之处,在于恰当地处理了抽油杆变杆径和变杆材处位移的计算。通过实例计算,证明该方法是可行的。

CALCULATING SURFACE DYNAMOMETER CARDS FOR SUCKER ROD PUMPS WITH AN IMPROVED FINITE DIFFERENCE TECHNIQUE

This paper presents the difference equation for calculating displacement of rod string at any position, which is based on the dynamic model of sucker-rod pumping systems. It can be used not only in single rod string but also in multiple rod string which consists of different rod sizes and materials. This method is different from the predicting models pioneered by Gibbs and Schafer in that properly deals with the calculation of displacement at the position of change in rod size and material. Calcultions demonstrate that this method is practical.