Beam Pumping Unit System Dynamics Analysis And The Dynamometer Card Simulation Of Polished Rod

Beam pumping unit, which is one of the most important mechanical oil extractionequipment, has been widely applied in the oil exploration field because of its superiorstructural properties. However, great side effect was caused since the beam pumping unit haslong been alternating loads, which can result in malfunction. Currently, fault diagnosis ofbeam pumping unit mainly depends on the measured light rod dynamometer. This method isboth time-consuming and inefficient for its longer measurement cycle, moreover installationof power meter were required where measuring. In recent years, research on indirectmeasurement methods of rod dynamometer is popular, motor power; speed and current wereneeded to work out the dynamometer. Value of loss power remain unchanged, transmissionefficiency of the belt drive, gear box and of pumping four-bar linkage considering as aconstant, all these factors will result in low accuracy and high relative errors in dynamometersimulation. In this paper, variation feature on Electrical parameter of beam pumping unitunder alternating load were systematic studied, mathematical model were established and roddynamometer were obtained using numerical simulation method. Researches were done onmotion characteristics of ground device, dynamic characteristic and transmission efficiency ofbeam pumping unit. the results show that a simulation model of CYJY10-3-37HB beampumping unit was built on ADAMS software, suspended beam pumping unit displacementcurves, velocity curves and acceleration motion characteristics curves were obtained, themaximum pumping suspension displacement is2.99m, the upper and lower suspension pointstroke peak velocity was0.88m/s and-1.001m/s respectively, the upper and lower peakacceleration stroke suspension point was-0.766m/s2and0.642m/s2.The fitting relationship ofasynchronous motor stator phase currents with electromagnetic torque and stator current withslip ratio were given out depending on asynchronous motor model, established onelectromagnetic simulation software Ansoft.In the efficiency analysis of ground installationsbeam pumping unit, the average transfer efficiency of belt transfer, gearbox and the four-barlinkage pumping were90.4%,82.5%and87.3%, respectively. Combined instantaneoustransfer efficiency of the beam pumping unit ground equipment, the relationship curve ofasynchronous motor stator phase currents and electromagnetic torque and pumping motioncharacteristic curve, using numerical simulation method to obtain a light pole dynamometer,dynamometer simulation program were created based on measured electrical parameters.Compared with measured dynamometer card, the maximum hanging point dynamometer loaderror of simulation is1.58%, the minimum is9.83%and relative error of dynamometer area is8.26%.