Abstract:With the increasing use of rod pumping units in heavy oil wells, the problem of viscous friction loads on sucker rods has become increasingly significant. At present, the equivalent damping coefficient is usually used to calculate the viscous friction load, but it cannot accurately reflect the change of the viscous load, which causes the design of the pumping unit to be unreasonable and the efficiency is not high. In this paper, aiming at the heavy oil in the tube, the dynamic equation of the liquid in the tube is established, and the velocity distribution of the liquid in the tube is solved. Based on this, combined with Newton's internal friction law, the calculation method of the viscous friction load of the sucker rod column in heavy oil well is formed. Taking a heavy oil well in Shengli Oilfield as an example, the calculation and analysis of the viscous friction load of the sucker rod column is carried out, and the change of the viscous friction load of the sucker rod in one motion cycle is obtained. Through the sensitivity analysis, it is concluded that increasing the sucker rod diameter and the tubing diameter or reducing the plunger diameter will increase the viscous friction load of the pole on the upstroke; increase the tubing diameter or reduce the sucker rod diameter will make the viscous friction load of the column smaller on the downstroke, but the change of the plunger diameter has no effect on the viscous friction load of the column. The research results provide a theoretical basis for the design of heavy oil well pumping unit and the selection of sucker rod.