INFLUENCE OF TEMPERATURE DEFORMATIONS ON THE FRICTION FORCE IN A PLUNGER PAIR OF A SUCKER ROD PUMP
The article considers the results of an analytical and experimental study of the influence of temperature deformations on the friction force in a plunger pair of a sucker rod pump. It is shown that one of the causes of rod breaks in the lower part of the column is the forces concentrated in the pump, in particular, the resistance force between the plunger and the cylinder, which when pressed down causes compression, bending and destruction of the lower rods. In addition, these forces, counteracting the movement of the plunger, reduce its stroke length, degree of filling, and pump performance. The resistance between the plunger and the cylinder has a significant effect on the wear rate of the plunger pair and on the pump life. It is one of the main criteria for the quality of manufacturing a plunger pair. The main factors affecting the friction force in the plunger pair, i.e. design parameters of the pump, physicochemical properties of the pumped liquid, operating parameters of the pump, geological and technical conditions of the pump are considered. The thermal operation mode of the sucker rod pump due to the high reservoir temperature of the oil, heat generation in the pump itself, heating of the pumped liquid by the pump located below in the layout of simultaneous-separate oil production is considered. An analytical dependence of the influence of temperature on the friction force in a plunger pair of a rod pump based on existing experimental results has been obtained. To assess the effect of temperature increase on the friction forces in the plunger pair, a laboratory bench was developed containing the mechanism of reciprocating movement of the plunger in the pump cylinder, in which the polished rod of the reciprocating mechanism is equipped with a strain gauge and a dynamograph recording the load during the entire cycle of the plunger pair. The results of the experiments show that when the plunger moves in the cylinder, the plunger heats up to a greater extent than the cylinder, which leads to a decrease in the annular gap of the plunger pair and an increase in friction forces.