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.

As the number of subsea wells in deepwater environments increases, companies who operate in these regions continue to seek safer and more viable economic solutions for improving value realization through well intervention. Traditionally, subsea well interventions are conducted from heavy-weight, mobile offshore drilling units (MODUs) with riser packages. Unfortunately, these intervention operationsinvolve significant operating day rates with consequent NPV negative results. This paper discusses a riserless intervention that was performed from a dynamically positioned multi-support vessel (MSV) that involved setting and recovery of a mechanical flow-control device in a well with a water depth of approximately 1900 m in the South Atlantic Ocean. The technologies and methods used in this intervention proved that these difficult subsea operations can be performed in a much more flexible and financially viable fashion than previously possible with conventional methods. The techniques developed for this operation also mitigated safety concerns for personnel and equipment, while executing the potential high-risk riserless intervention with success. The paper will cover the record-breaking, light-weight intervention and the technologies used on this campaign that eliminated the need for a traditional MODU. Of particular interest is the unique vessel interface that allowed the operation to be performed safely and efficiently with slickline. This successful intervention opens new opportunities for safer and more economical interventions in the deep and ultra deepwater arenas.