In Azerbaijan oil production is carried out both in the offshore and onshore. Offshore production is carried out on special platforms, while the onshore exploitation carried out directly by a mechanized method. Thus, the object of study is downhole pumps, which consist of a surface mechanical transmission and downhole equipment. For direct mechanization of ground equipment, a device called rocking machine is used, consisting of transmission and converting mechanisms. The main task of the rocking machine is to ensure the conversion of the rotational motion of the engine into the up and down stroke of the plunger of the pump. The downhole equipment includes rods column that lift liquid from the well, a cylinder and a plunger. However, the existing classic rocking machines have some advantages as well as some disadvantages. In order to overcome them, developed new design solution of the sucker-rod pumping unit, which consisting of a crank-rope-movable counterweight system has been designed. As a result of the research carried out in the article, a progressive expression was proposed for determining the strength condition of the rods column, which is one of the main working elements of the rocking machine. Then, in order to specify the wells in which the rocking machine can be applied, the statement regarding the determination of the value of the linear density of liquid column based on the strength condition of the rod column was put forward. These, in turn, can be determined in which oil wells with specific physical characteristics of the rocking machine with the given technical characteristics can be applied. All this can contribute to the prevention of accidents that may occur due to the breakage of the rods column of rocking machine. The formula proposed in this paper can be applied not only to the existing classic rocking machines, but also to other new design of rocking machines.

The choice of rational designs of pumping units for lifting fluid from a well and the modes of their operation is one of the most urgent tasks in oil production. Despite the large amount of theoretical and extreme research, the solution of the problem in this direction cannot be considered complete, given that the dynamic characteristics of the movement of the well product and the kinematics of the well pumping unit are extremely complex. This article discusses the issue of determining the dynamic forces acting at the rod suspension point, in the new constructive solution of a beamless pumping unit depending on the angle of rotation of the crank and dimensionless kinematic parameter characterizing the relationship of the length of the crank to the length of the working part of the rope and the relative eccentric. Analytical dependencies are proposed to determine the maximum load at the rods suspension point depending on inertial and vibration forces.

The article presents the results of experimental studies to assess the loading and balancing of a new constructive solution of beamless sucker-rod pumping units. It is noted that the key factor that has the most significant effect on the mean time between failures (MTBF) is the right balancing of the pumping unit. The main purpose of the balancing device is the accumulation of potential energy during the downstroke and its release during the upstroke of the rod. It has been proved that the proposed additional balancing system (movable counterweight) which helps to reduce the uneven load on the electric motor and the power consumption of the pumping unit will also increase the efficiency of the beamless sucker-rod pumping unit. It was found that losses in sucker-rod pumps depend on the degree of balance of the counterweights. If the unbalance coefficient of the equipment is in the range from –5 to +5%, then the power loss due to unbalance can be ignored. In the current article, the authors propose a technique that allows to determine the energy characteristics of the electric drive of the pumping unit under conditions of a cyclically changing load and insufficient balance. It was revealed that when the balancer head passes from the upstroke to the downstroke and vice versa, there are sections with a negative value of the torque, which is explained by the influence of the inertial forces of the moving masses. This leads to shocks in the gearing of the reducer at the extreme positions of the cranks, increased wear and possibly to breakage of the teeth. Since it is not possible to completely eliminate this phenomenon, one should strive to limit the value of the negative torque by the correct balancing of the sucker-rod pump. In all cases, the change in the operating mode of a new constructive solution of beamless pumping unit requires new calculations, and requires changing the position and weights of movable and rotary counterweights (with combined balancing).

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The article addresses the issue of determining the dynamic forces acting on the rod suspension point during the operation of the well in a new construction design for a beamless pumping unit, depending on the angle of rotation of the crank and the dimensionless kinematic parameters, which characterize the relationship of the crank length to the rod length and relative eccentricity. It was found that the value of the dynamic loads in the rod column depends on the type of the rocking machine and on the direction the crank rotates. In addition, one of the adverse factors for the operation of the pumping unit is that the force at the rod suspension point is constantly directed downwards, and that it varies during the course of the polished rod down-and upstrokes, which leads to uneven loading of the electric motor. This mode of operation for the engine and gearbox is abnormal and comes with a sharp decrease in their efficiency. To equalize the load on the gearbox and engine during one cycle of work, and to reduce the engine power needed to carry out the balancing process, a combination of movable and rotary counterweights is applied in the proposed design to balance the pumping unit. To this end, an investigation was made of the method of balancing a new structural design of the pumping unit and proposed analytical expressions for determining the weight of the movable and rotary counterweights when moving the rod suspension point up and down using combined balancing. The article discusses options for determining the dynamic forces in both a non-balanced (without using any counterweights) and a combined balanced (by using both moving and rotary counterweights) oil pumping unit.