游梁式抽油机井井下泵功图测试方法

Test approach of downhole pump diagram for beam bumping wells

提出了一种利用加速度传感器测量抽油泵冲程从而得到游梁式抽油机井井下泵功图的直接测试方法,并进行了实验验证和现场测试。分析了加速度传感器输出的带有冲击干扰的低频弱信号的特性,对周期信号及其漂移进行了建模分析,得出了长时间积分累计误差及其对测量结果的影响。根据消去原理设计了隔直去噪滤波器,建立了其数学模型,通过隔直去噪滤波器可将漂移分量从采集信号中分离出来。实验验证及现场测试结果表明:原始加速度数据经隔直去噪滤波器滤波和二次积分后能够得到无漂移位移信号,从而得出井下泵功图,数据测量精度在±2.0%以内,且测量误差随着冲次增大而减小;提出的井下泵功图测试方法可实现对泵效的计算和冲程损失直接测量,为游梁式抽油机工艺分析提供依据。

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 fin＇ther 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.