Avaliação dos mecanismos de desgaste de componentes de BCS operando em meio com água salgada, abrasivo e gás CO2

Abstract

Submersible centrifugal pumping is one of the methods of artificial oil lift used in wells that lack sufficient energy to naturally lift it to the surface. Submersible centrifugal pumps (SCP) used in this application operate under severe conditions due to the presence of water, sand, and gases in the wells, causing operational drawbacks such as loss of efficiency and critical damage to internal components. In real situations, the effect of corrosion caused by CO2 is an additional concern in the degradation of structures and oil exploration equipment, including SCP components such as rotors, diffusers, and sliding bearings. The main objective of this project is to conduct SCP testing with CO2 gas injection (free) in a medium of saltwater and abrasives to minimize oxygen levels to below 500 ppb and assess the effect of this gas presence on pump component degradation. The mass of all pump components was measured before and after the tests to identify the most worn components. Subsequently, the mass loss was calculated, and critical components were identified. Microscopic degradation mechanisms were identified for these components using scanning electron microscopy (SEM), which also enabled access to the chemical composition of various mechanical components of the pumps. The obtained results indicated that first-stage components showed the highest mass loss rate (10.78 g/t – variation of 7.66%), while second and third stages presented rates of 10.11 g/t (variation of 7.21%) and 8.06 g/t (variation of 5.80%), respectively. Regarding wear mechanisms, it was observed that wear of SCP components occurs differently, including but not limited to: corrosion, erosion, and abrasion.