煤层气井有杆泵排水采气设备示功图

煤层气井示功图直观表现了悬点载荷的变化规律，可为有杆泵设备设计计算提供重要依据。基于有杆排采设备的运动学和动力学分析，建立了计算悬点各载荷的数学模型，给出煤层气井不同开采过程的静力和动力示功图。实例分析结果表明，静力示功图接近于稳定生产后的示功图，代表了悬点载荷变化的基本规律，是分析实际示功图的基础；动力示功图在考虑动载荷的影响后，呈现出波动和偏斜的形状，考虑摩擦力的作用后，示功图的上缘向上平移，下缘则下移。煤层气井动载荷和摩擦力所占的比例分别达到15%和5%，这就加大了悬点载荷的变化幅度与不平衡性。随冲次的降低，示功图的下缘远离零线，上缘则逐渐远离下缘，而且惯性载荷和振动载荷影响的减小，使得上下缘的倾斜度逐渐降低，波动幅度不断变小。煤层气井杆管总变形量较小，与冲程的比值仅为10%左右，且随冲次的降低，总变形量和静变形量逐渐增大，而动变形量不断变小。

Dynamometer card of sucker rod pumps in coalbed methane wells

The dynamometer card can illustrate the variation of polished rod load and provide the basis for design calculation of sucker rod pumps in coalbed methane (CBM) wells. Based on the kinematic and dynamic analysis of the pumping system, the mathematical models of the loads of polished rod were developed. The static and dynamic dynamometer cards were obtained with every phase. The results show that the static dynamometer card is approximately the actual one during the steady flow production, shows the variation of static load and will help to analyze the actual one. The dynamic dynamometer cards present the shape of fluctuation and deflection due to the dynamic loads, and their upper and lower parts are removed from two ends respectively due to the friction loads. The ratio of the dynamic and friction to polished rod is calculated as 15% and 5% respectively, which increases the variation range. For dynamometer cards, their two parts deviate from the null line, the slopes decrease gradually, and the rangeability becomes smaller and smaller due to the low ratio of dynamic to polished rod load. Besides, the total string deformation in CBM wells is small and just 10% of stroke length. And the total and static deformations are enhanced while the dynamic ones decrease with the decrease of the pumping speed.