Abstract
In order to calculate a column of pumping rods as a mechanical system with concentrated masses, to determine dissipation coefficients, we applied a traditional method of analytical mechanics. A mathematical model is developed of longitudinal oscillations of a three-stage conditionally vertical column of sucker rods using the functions of displacement and load of its separate stages. Dependence for determining the dissipation coefficient of oscillations is derived from the solution of the system of equations. In accordance with the chosen set-up of a three-stage column of sucker rods, we examined a change in the dissipation coefficient of oscillations depending on the relationship between the rigidities of its stages. A change in the relationship between rigidities of the stages was carried out by changing their material. It was found that for the selected set-up of a column of sucker rods, the use of a fiberglass stage instead of that made of steel reduces its rigidity by approximately 4 times, and increases the dissipation of oscillations almost as much. Such approach makes it possible to prevent the phenomenon of resonance in the operation of a SR column during transition modes under the action of alternating load.
Highlights
In the process of oil extraction by downhole rod pump installations (DRPI), a column of sucker rods (SR) in a string of pumping-and-compression pipes (PCP) is exposed to both static and dynamic load
Reliable information about the loading of a SR column can be obtained by the application of dynamometry at different DRPI operational modes [1]
This approach has a significant shortcoming in that it is impossible to employ the results of dynamometry at the stage of completing a SR column when the cost and time of making changes in its design is minimal
Summary
In the process of oil extraction by downhole rod pump installations (DRPI), a column of sucker rods (SR) in a string of pumping-and-compression pipes (PCP) is exposed to both static and dynamic load. Reliable information about the loading of a SR column can be obtained by the application of dynamometry at different DRPI operational modes [1]. A development of dynamic processes over time known in advance makes it possible to evaluate the capability of mechanical system “SR column – fluid – PCP string” to resist external stresses. It contains information about the structure of the system, degree of its nonlinearity, dissipation mechanism of oscillation energy, allows evaluation of its stability and the capability for the self-excitation of oscillations. An alternative method of estimating the dynamic loading of a SR column is mathematical modeling of oscillating processes, which basically comes down to constructing and solving a system of differential equations of motion
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call