In order to solve the problems such as the working status cannot be identified for the surface equipment including the pump-wells,high-cost measurement and maintenance etc.,a new diagnosing model was deduced and established for the working status of the belt-pump-unit wells on the basis of the dynamometer cards.With the help of the energy conservation law and the motion laws of the pumper suspension center,the mathematical model was built to calculate the electrical diagrams by the dynamometer cards,and moreover eleven kinds of the electrical diagrams under the typical working status of the pumpers were presented,characteristically analyzed and furthermore the characteristic values were extracted,finally the diagnosing model of the working status was established on the basis of the values.The calculation and analysis of the field case show that there are basically coincident between the achieved electrical diagrams and actually measured ones,the average relative errors of the electrical power on the up and down-stroke plats,power curve are 6.32％,7.16％ and 5.81％ respectively;the coincidence rate is 100％ between the diagnosed results from the electrical diagrams and those of the underground operating conditions from dynamometer cards,and moreover the former can more accurately judge the working status of the surface instrument i.e.the pump-unit wells.The study achievements can improve the diagnostic reliability,expand the diagnostic range and provide the technical support for the intelligent analysis and optimization decision of the oil production system.%为了解决示功图无法判别抽油机井地面设备工况、实时测量和维护成本高等问题,推导建立了基于电功图的皮带式抽油机井工况诊断新模型.根据能量守恒原理和皮带式抽油机悬点运动规律,建立抽油机井地面示功图计算电功图的数学模型.基于该模型,建立11种皮带式抽油机井典型工况下的电功图图版,并对电功图图版进行特征分析和特征值提取,建立基于特征值的电功图工况诊断模型.现场实例计算分析表明:计算得到的电功图与实测电功图基本一致,上冲程平台功率值、下冲程平台功率值和功率曲线的平均相对误差分别为6.32％、7.16％和5.81％;电功图诊断结果与根据示功图进行井下工况诊断结果的符合率为100％,且电功图能够准确地判别抽油机井地面设备的工况.研究结果能提高工况诊断结果的可靠度与诊断范围,为采油系统智能分析和优化决策提供技术支持.
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