EVALUATION OF INSTALLATION LIMITS OF EQUIPMENT IN DIRECTIONAL WELLS EQUIPPED WITH ELECTRICAL SUBMERSIBLE PUMP
electrical submersible pumping; deviated wells; artificial lift; dogleg severity; stresses and deformations.
The installation Electrical Submersible Pump (ESP) systems in directional wells must respect maximum dogleg severity (DLS), otherwise permanent deformations and premature failures of the ESP can occur. On the other hand, the establishment of excessively strict limits can lead to design solutions in which the pumping strig is not deepened sufficiently, in a way that results in a loss of well potential, which can even make the use of ESP unfeasible for economic aspects. Due to the lack of norms and standards that explicitly define these limits, it is necessary to use methodologies for calculating stresses and displacements in the ESP string, with the support of specialist software, which allow verifying whether the design solution meets the requirements of the equipment. In this context, this study proposed to analyze the stresses and displacements in ESPs installed in wells with high curvatures, carried out in an onshore production field over the last 23 years, in order to correlate the observed efforts with the operational performance achieved. For this purpose, the ASAP (A Stress Analysis Program) module of the AutographPC® software from Baker Hughes was used. Additionally, a multivariate statistical model was generated, which allowed a good prediction of tension values in 92% of the cases analyzed. The observed results indicate that ESP strings from the 400 series and with a length of up to 20 meters, installed in 7” casings, can go through DLS of up to 8º/30m without relevant compromising of the operational performance. Findings can contribute to the establishment of design criteria, normative parameters and practical industry recommendations for ESP systems.