杆式抽油井油管受力和振动分析

Force and vibration analysis of tubing string in rod-pumped wells

通过分析杆式抽油井油管的受力，认为下冲程时液柱对油管下端的作用力不仅包括油管和抽油杆之间环形空间内的液体重量，还包括抽油杆所占空间的液体重量，且抽油杆相对于液柱向下运动的摩擦力也将通过液柱作用在油管下端。在杆式抽油井抽油过程中，动载荷是引起油管自由振动的原因。用振动方程求出的大庆采油六厂喇－2111井的油管自由振动频率与实际测得的自由振动频率相吻合。

By means of the force analysis of the tubing string in a rod-pumped well, it is indicated that, during the down stroke of the pump, the forces on the lower end of the tubing string applied by the liquid column include the weight of the liquid in the tubing-rod annulus as well as the weight of the liquid in the space occupied by the rod string. In addition, as the rod string moves down against the liquid column, the friction between them will be applied on the string's lower end. In the course of rod pumping, the free vibraion of the tubing string is caused by the dynamic load. The frepuency of the vibration is obtained by solving the vibration equations, and the calculated result conforms to the measured value of the vibration frequency.