Erosion of alloys used for the stages of electrical submersible pumps

Abstract

Judicious selection of the material used for the stages of an electric submersible pump (ESP) is crucial for a prolonged service life. Working in high-velocity fluids carrying solid particles, the stage surfaces are subjected to solid particle impingement and thus erosion defects arise. Moreover, subsequent erosion-corrosion synergy brings additional threats to the ESPs operating in corrosive environments. In this report, jet impingement tests were conducted to evaluate the performance of three alloys under erosive and corrosive conditions. The tested materials include two Ni-Resist cast irons — wear-resistant materials commonly used for ESP stages — and one superduplex stainless steel (SDSS) that is famous for high strength and extraordinary corrosion resistance. The erosion rate of each material, along with its dependence on jet impingement angle, is quantified in terms of overall volume loss and localized depth loss. Tap water and salt solution are used as particle carrier in parallel to study the synergy between erosion and corrosion. The erosion mechanism of different phases, as well as its dependence on particle impingement conditions, are discussed. Finally, the applicability of substituting Ni-Resist cast irons with SDSS to cope with highly corrosive conditions is assessed based on the experiment results.