Jubarte Phase II comprises 15 production wells and seven injectors producing to the P-57 floating production, storage, and offloading (FPSO) platform. Wellheads are in 1,400 m of water, and each well produces to a seabed pumping module—módulo de bombeio (MoBo) in Portuguese—that houses a 1,500-hp electric submersible pump (ESP). A limited track record for high-power and high-flow-rate subsea ESP systems and the operational challenges associated with seabed production created uncertainty that required proper risk management techniques:

• Jubarte holds a 17.1° API heavy oil with a tendency to form strong emulsions, which, coupled with an expected early water breakthrough, posed a major challenge to ESP and MoBo performance.
• Locating ESPs on the seabed results in wide pressure and temperature swings during normal cycles of operation.
• Lengthy shutdowns and the possibility of hydrate formation required a thorough analysis of the process loops.

To address these challenges while operating an offshore oil field with ESPs as the main form of artificial lift required a comprehensive approach that would not only rely on installation of high-technology equipment, but would also seek to extend the traditional concept of industrial process control to the management of MoBo- ESP systems.

Five years after first oil and a few months after the start of its third phase, Jubarte reached a maturity old enough to demand new breakthroughs in the chase for improving subsea system uptime. In this matter and in order to reach the expected run life, the development of a thorough “ESP culture” became a key element connecting the different teams involved in the operation. The synergy created allowed the provision of timely solutions to face challenges that cannot be approached only with the best equipment currently available in the industry.

This paper describes the philosophy of operation in the Jubarte field and provides examples of how diverse problems related to flow assurance, equipment operation, and remediation work were addressed. Methodologies described apply to different aspects of the operation, such as the descaling treatment of a subsea ESP without a workover (a first for the operator), determination of the correct medium-voltage variable frequency drive (VFD) parameterization, the success of starting up an ESP on first attempt, and the effectiveness of a demulsifier injection in a system that can see viscosity increase tenfold.

The experiences gathered and results obtained with the operation of MoBo-ESP systems in Jubarte Phase II have encouraged the operator to continue development of Jubarte Phase III and the neighboring Parque das Baleias using a similar solution.