MOBO ESP Interventions

Abstract

The Shell operated Parque das Conchas fields of the Brazilian deepwater block BC-10 utilize ESPs as the sole artificial lift method. Unlike traditional in-well deployed ESP systems, the ten BC-10 ESPs are deployed inside relatively shallow – 100m - caissons distributed across three subsea gathering areas, or Artificial Lift Manifolds at water depths from 1650 to 1900m. The integrated caisson, ESP and inflow/outflow valving is deployed and retrieved as a single unit and hence derives the name of a Pump Module, or Modulo de Bomba in Portuguese, or MOBO for short. As ESPs have much shorter run lives compared to the approximate 25 year field life, the BC-10 subsea operations asset team is responsible for managing and executing the rig based ESP replacement intervention campaigns, or Mobo interventions. As of 2015, nine ESP replacements have been executed in four campaigns. This paper examines the diverse aspects associated with the ongoing efforts to maintain the artificial lift system of BC-10 before, during and after a rig intervention campaign. Topics covered include the ESP failure analysis, equipment sparing philosophy, equipment and tooling preparations, offshore execution, vendor relationships and overall project management. Finally, learnings obtained during the four years of near continuous preparation and execution of MOBO interventions are discussed along with some planned future improvements.