基于系统效率最高的抽油机井合理流压研究

确定抽油机井合理流压是采油工程与油藏工程的重要研究内容。本文建立了以系统效率最高为评价指标的抽油机井合理流压仿真方法,具体包括:基于抽油机井井筒油气水多相稳定流动的泵排出口压力与油井产液量的耦合仿真模型;有效功率的仿真计算方法;基于抽油杆柱轴向振动与悬点示功图仿真的电动机输入功率仿真模型;系统效率与流压、油藏参数、抽汲参数之间函数关系的仿真模型;给定流压条件下系统效率极值的仿真模型;系统效率极值随流压的变化规律以及合理流压的确定方法。仿真分析结果表明:流压对抽油机井系统效率有显著影响,优化流压可以显著提高系统效率;含水率、气油比与饱和压力等油藏参数是影响合理流压的主要因素。

Study of reasonable flowing pressure of rod pumping wells based on maximum system efficiency

It has been a significant issue to calculate the reasonable flowing pressure of the rod pumping wells is the important scientific research subjects in the petroleum engineering and the oil reservoir engineering field.In this paper,the maximum of the system efficiency of the rod pumping unit is taken as the evaluating index of the reasonable flowing pressure,and a method is developed for calculating the reasonable flowing pressure of rod pumping wells.Using this method,five simulating models are set up as follows:1) the effective power of the rod pumping wells based on the multiphase flow;2) the input power of the motor based on the simulations the dynamic behaviors of the sucker rod string and the dynamometer cards of the polished rod;3) the functional relations of the system efficiency with the flowing pressure,oil reservoir parameters and suction parameters;4) the maximum system efficiency at a given flowing pressure;5) the relations of the maximum system efficiency with the flowing pressure.The results of simulation show that:1) the system efficiency of the rod pumping well is greatly affected by the flowing pressure,and the system efficiency can be increased by optimizing the flowing pressure;2) the oil reservoir parameters of the water content ratio, the gas/oil ratio and the saturation pressure are the major parameters which affect the reasonable flowing pressure.