This paper prepared for 2018 OTC Offshore Asia explores the current history of electrically driven functionality for subsea production systems.
It is expected that co-existence of hybrid electrohydraulic and all-electric functionality will dominate the market for subsea tree and manifold control short term. Electric choke and manifold valve actuation offer many advantages as proved successfully during the last 16 years, e.g. related to modularity and flexibility, with zero discharge, with high operational speed and high positioning accuracy, along with CAPEX and OPEX benefits. Performance of systems such as Statoil's Asgard Subsea Gas Compressor is a game changer that will make all-electric valve control base case also for future subsea processing plants.
Reliability & Availability concerns were the major concerns by many operators for not switching to all-electric technology. The excellent reliability of trickle charged batteries in subsea systems, combined with modern safety electronics eliminate the traditional actuator spring as failsafe mechanism power source. All of this has simplified the equipment, reduced the size, and enables continuous equipment status monitoring.
Competitive all-electric systems are expected to be introduced in stages, starting with infill wells. This will eliminate the risk of new technology for the best business cases, being long distance gas fields, water injectors and deep water systems.
Subsea all-electric solutions benefit from general technology developments in other industries. Full utilization is however slow in the subsea market, hampered by current rules and regulations, risk aspects and conservative mindsets. All-electric solutions need Champions and a continued successful staged development initiatives to realize their full potential for significantly reducing subsea field development capital and operational cost.