Research On Monitoring Method Of Oil Well Dynamic Liquid Level Based On Electric Power Graph

The dynamic liquid level parameter of the beam pumping system is the key monitoring data for dynamically predicting the production of oil wells,and also an important indicator for determining the reasonable working system and reasonable sinking degree of oil wells.However,because the dynamic level of the oil well is located hundreds of meters or even thousands of meters downhole,it is difficult to monitor in real time due to the reservoir capacity constraints and the reciprocating motion of the sucker rod.Aiming at the problem that the acquisition of electric power in the traditional electric power graph curve of the oil well condition is restricted by the third-party power analyzer,and the balance block in the pumping system reduces the power fluctuation of the motor during the stroke and other factors,the accuracy and reliability of the analysis method to reduce the problem,this paper proposes to make full use of the advantages and reliability of electrical parameter acquisition,directly analyze the three-phase electrical power of the pumping motor voltage and current parameters,based on the distributed parameter motor model,consider the iron core and other losses,and obtain the motor output electrical power,reduce the input of secondary instruments and improve the accuracy of power acquisition.According to the energy conservation theory of the closed system,the stroke cycle energy index is introduced into the power graph analysis to improve the analysis accuracy of the electric prower graph.Based on this,the improved electric power graph method was introduced into the online monitoring of the oil well dynamic liquid level.The field application of the oil field verified the effectiveness of this method.The main research contents of this article are as follows:This paper analyzes the working principle of the beam pumping system in detail,and establishes the system dynamics and power model suitable for the beam pumping system;the system energy flow transfer mechanism is analyzed from the system level.The energy consumption and transmission efficiency were studied,and the coupling process of the motor(electrical)with the reduction gearbox,four connecting rods and sucker rod(mechanical)was analyzed,which laid a theoretical foundation for the identification and monitoring of the dynamic liquid level of the electric power graph.After fully considering the influencing factors of friction,vibration,elastic deformation and transmission efficiency of the moving parts on the ground(motor,gearbox and four connecting rods)and downhole(sucker rod),the voltage and current parameters of the pumping motor are directly used analyze its three-phase electric power,electric power and dangling point displacement to form an electric power graph,infer the relationship between conductive power and dangling point load,and further convert it into an indicator graph.Introduce the stroke cycle energy index into the power graph analysis to optimize the electric power graph accuracy.Use Gibbs equations to calculate the oil well dynamic liquid level,and provide data for monitoring the dynamic liquid level of the electric power graph by technical support.Through the off-line simulation of an actual production oil well,the method and the field high-precision power measuring instrument test results and the dynamic liquid level data results under the same working conditions are compared and analyzed,and the oil well dynamic liquid based on the electric power graph is verified in this paper The feasibility of surface monitoring methods.Combined with the measured data of the four oil wells monitored by an oil production plant,the electric power curve was obtained from the method based on electrical parameters,the method with the help of a high-precision power analyzer,and the method with the help of a common-precision power analyzer.Comparative analysis of the surface and the results show that the electric power curve obtained based on the electric parameters is close to the shape trend of the electric power curve measured by the high-precision power analyzer and the size of the extreme point of the up and down stroke power.The error is small.Using the data of 4 oil wells on site of an oil production plant,the relative errors of the measured actual liquid level heights on the spot using this method,the dynamometer method and the echo method are compared respectively.The dynamometer method has higher accuracy and provides an effective on-line monitoring method for dynamic liquid level for oil well production.It also analyzes the changes of the electrical power graph when the dynamic liquid surface changes slightly.The results show that the electrical power graph obtained by the electrical parameters with the zoom function has obvious observability when the dynamic liquid surface changes little.Finally,the graphical programming language LabVIEW was used to design and develop the online monitoring software for oil well production dynamic liquid level,real-time acquisition of the three-phase electrical signals of the pumping unit motor was carried out,and data processing was carried out to achieve the dynamic graph of electric power graph.The purpose of visual monitoring is to provide technical support for oil well dynamic liquid level monitoring and to facilitate the application of oil well production scheduling platforms.