Energy dissipation analysis of oil wells sucker rod string

Abstract

Sucker rod pumping systems are well-known artificial lift methods, thereby improving the efficiency of oil production. However, the periodic movement performed by the string makes the system susceptible to mechanical failures, promoting operational shutdowns. This paper presents a new approach to the vibrational analysis of the sucker rod string through a study of energy decay. The damped wave equation representing the oscillatory motion of the sucker rod lift system was solved analytically, and the energy of the solution was characterized by analyzing its behavior in space and time. The results show that the energy has a dissipative nature, promoting the vibrational attenuation in three different exponential decay forms. The results allow to characterize the damping limits of each exponential decay type. The approach proposed in this paper, by energy decay analysis, can serve as base to the development of new methodologies capable to detect anomalies and optimum operational conditions in sucker rod pump system.