| Summary: | A direct test approach of downhole pump diagram for beam bumping wells was presented using acceleration transducer to measure the pump stroke, and it was verified through laboratory experiments and field tests. The feature of the low-frequency and weak signal exported from the acceleration transducer with impact interference was analyzed. The periodic signal and its drift were modeled to work out the accumulative error of long-term integration and its influence on measurement results. Based on elimination principles, the DC-blocking and denoising filter was designed and its mathematical model was established. Through the filter, the drift component can be separated from the acquired signal. The laboratory experiments and field tests indicate that, the displacement signal without drift can be obtained from the initial acceleration data through filtering and quadratic integral, thus the downhole pump diagram can be obtained; the data measurement error is within ±2.0%, which will be further reduced with the increase of stroke times; the test approach of downhole pump diagram can realize the calculation of pump effectiveness and the direct measurement of stroke loss, thereby providing criteria for the process analysis of beam bumping well. Key words: pump unit, downhole pump diagram, stroke, acceleration, filter
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