定向井有杆抽油系统井下耗能分析

针对现有抽油系统井下能耗计算公式难以确定杆液、杆管间摩擦耗能的缺陷,提出一种比较精确的分析方法。首先,对杆管间库仑摩擦力以及杆柱各节点的弹性运动速度进行了计算;其次,对抽油系统中库仑摩擦力、粘滞阻尼力以及盘根盒摩擦力在一个抽油周期内的耗能进行了分析,并根据悬点功图计算出一个抽汲周期内井下输入功,进而对井下效率进行了计算;最后给出了计算实例。计算结果表明,杆柱弹性运动速度引起的粘滞阻尼力耗能不能忽略。

Energy Dissipation Analysis of the Sucker-Rod Pumping System of Directional Well

With an aim at the down-hole energy dissipation calculation formala for the existing sucker-rod pumping system difficult to determine the defects of friction energy dissipation among the rod string and liquid as well as the rod and pipe,this paper suggests a more precise and analytical method.Firstly,the Coulomb friction force between rod string and pipe and the elastic velocities of the rod nodes are computed.Secondly,the analysis of energy dissipation in one production period caused by viscous damping force,Coulomb friction force and friction force between rod string and stuffing box are performed.Thirdly,the input down-hole energy in one production period is calculated according to the surface dynamometer card.Whereby the down-hole efficiency is calculated,with the real calculated examples given.The calculated results indicate that the energy dissipation of viscous damping force caused by the elastic velocity of rod string can not be ignored.