两层分采同步抽油系统故障诊断模型的数值分析法

NUMERICAL METHOD FOR THE DIAGNOSTIC MODEL OF SUCKER-ROD PUMPING SYSTEM OF DOUBLE-LAYER SEPARATE RECOVERY

建立两层分采同步抽油系统的故障诊断模型 ,研究在实心抽油杆与空心抽油杆的界面处空心泵对应力波的影响 ,给出抽油杆柱不同杆段的波动方程的显示差分格式 ,提出一种故障诊断模型的反问题计算法。用此算法可在缺少一个边界条件的情况下求解故障诊断模型 ,获得抽油系统各个工况下抽油杆柱任意截面的受力状态 ,从而绘制出两层分采同步抽油系统的空心泵示功图和管式泵示功图。将此算法与模式识别技术相结合可对两层分采同步抽油系统的故障进行诊断。

A new sucker rod pumping system of double layer separate recovery is developed in order to solve the interbedded disturb problems of multilayer heterogeneous oil field radically. The present fault diagnosis technique can't well suit to diagnose the new pumping system. The key to the down hole fault diagnosis of pumping system lies in obtaining the down hole pump dynagrams. The diagnostic model of sucker rod pumping system of double layer separate recovery is established, the effect of hollow pump upon the stress wave is studied on the interface of solid and hollow sucker rod, the difference schemes of the wave equation for various cross sections of sucker rod string are given, and a reverse problem algorithm of the diagnostic model is proposed. This algorithm may be applied to solve the diagnostic model under the lack of one boundary condition, thus the stress of arbitrary cross sections of sucker rod string under various states is obtained, and the dynagrams of hollow and tube pump can be drawn. We will combine this algorithm with the mode identification technique in order to diagnose the faults of sucker rod pumping system of double layer separate recovery. The correctness of the algorithm is verified with the measured ground dynagrams of experimental wells.