OUTPUT-ONLY MODAL ANALYSIS OF AN ELECTRICAL SUBMERSIBLE PUMP USING TIME AND FREQUENCY DOMAIN TECHNIQUES

Jairo Alvaro C. Huamani¹; Ulisses A. Monteiro¹; Ricardo H.R. Gutiérrez¹; Antonio Carlos Ramos Troyman¹; Luiz A. Vaz¹

¹ Federal University of Rio de Janeiro (UFRJ)

doi:10.20906/CPS/CILAMCE2017-0428

Resumo

Electrical submersible pumps (ESPs) are applied in the petroleum industry to pump large amount of fluids from subsea deep wells. Currently, ESPs are responsible approximately for 10% of the world's crude oil production. When high flow rates are required, the gas lift and the ESP methods are the two available technologies that can be applied. ESP systems are much more complex and less reliable than the gas lift method, but they are more efficient and able to yield higher flow rates and pressure. ESPs are installed inside or near the production well, which means that in offshore ultra-deep water scenarios, maintenance is prohibitive because of the need for expensive and unavailable rig platforms. Assembly errors and manufacturing defects must be avoided to make the method feasible and to prevent premature failure and, this goal, can only be achieved through rigorous quality control, operations procedure, qualification and dynamic tests. In this paper, the modal parameters of an ESP installed in a mock well were experimentally identified using the Eigensystem Realization Algorithm (ERA) and Enhanced Frequency Domain Decomposition (EFDD) techniques. In the experimental test, an impact hammer was used to excite the ESP structure in a location near the wellhead, in the production pipe, not directly at the frame of the equipment and vibration signals were acquired along the ESP structure. Results showed that the impact test is a useful method for modal parameters identification of ESP's, in the operating range. However, due to the location where the impacts were applied, the lower vibration modes, outside the operating range, were not excited.

Palavras-chave: Electrical Submersible Pump; Mock Well; Output-Only Modal Analysis; Eigensystem Realization Algorithm; Enhanced Frequency Domain Decomposition