Study On Pump Efficiency Parameters Detection And Control Of Pumping Unit

Liquid supply shortage can cause the rod pumping system oil discharge reduction,system pump efficiency decreased and energy waste.Depend on the downhole liquid supply adjust the running state of rod pumping system accurately and timely has become a important research direction.Aiming at the problem of low pump efficiency,this paper mainly research on the following several aspects:(1)The working principle of rod pumping system was analyzed,emphasis research concepts of indicator diagram,and distinguish between several kinds of typical fault indicator diagram.As an important basis to judge the oil well production status,measuring and mapping the parameters of the indicator diagram directly affect the pump efficiency parameter measurement accuracy.Selecting type CSF-3GB load sensor to measure the load parameters of pumping well,designing load signal acquisition circuit.In order to verify its effectiveness,the indicator diagram load signal acquisition circuit is simulated.(2)By extracting indicator diagram of load parameters,setting the model of pumping system boundary and initial conditions to set up the rod pumping oil system mathematical model.Then using Fourier transform method to salve the Gibbs wave equation.The ground load function and displacement function can be converted to downhole pump load function and displacement function,thus completed the transformation from indicator diagram to pump indicator diagrams.Finally,the relationship between the valve opening-closing position and effective stroke in pump indicator diagram was analyzed.The curvature change rate of pump indicator diagram was calculated by five point curvature method.The effective stroke of the plunger is determined,and the pump efficiency of the rod pumping system is calculated.(3)Study of the control strategy of the pump efficiency for sucker rod pumping oil system.The coordinate transformation principle of vector control and mathematical model of asynchronous motor is analyzed,the vector control system of asynchronous motor based on voltage space vector(SVPWM)is established.By control the speed of beem-pumping unit,the stroke frequency of rod pumping system is matched with the liquid state of the oil well,achieve the purpose of improving the pump efficiency.The simulation model ofasynchronous motor vector control system based on SVPWM was built by Matlab/Simulink,the effectiveness of vector control system is verified by simulation.(4)Design experiment program,set up experimental platform of indicator diagram load signal acquisition circuit,according to a large number of experimental data,the pumping efficiency of rod pumping system was compared after the experiment,the effectiveness of pump efficiency control system is verified.