World-First All-Electric Subsea Well

Abstract

K5F3, the world's first fully all-electric well of the subsea industry, has been opened to production on 4 August 2016. This paper will present the benefits of electric subsea control compared with current state-of-the-art hydraulics methods, describe R&D projects that led to this first industrial application, and outline the main project phases and milestones. Difficulties encountered will be presented, and lessons learned will be disclosed. Finally, this paper will present future plans for subsea electric control going forward. The current state of the art for subsea well control is based on hydraulic technology. Hydraulic fluid is supplied from a host facility to the subsea wells through dedicated tubes within an umbilical and is distributed to the wells, in which the typical components are the manifold, Christmas tree valves, and downhole safety valve. The all-electric subsea well consists of an electric subsea Christmas tree, electric downhole safety valve, and associated subsea control modules. Valve control is established via an electric cable. The main driver for this innovation is cost reduction. Umbilicals are complex, difficult to install, and highly expensive. Replacing hydraulic fluid tubes by an electric cable within the umbilical can provide a 15% cost savings over a 30-km step-out. Implementing electric technology for Christmas tree valves and downhole safety valve control can also generate a further 10% cost reduction. All-electric subsea control is also an enabler for subsea processing innovations for more cost-effective subsea developments in a low oil price context. A global 30% to 40% reduction, outside of market effects, is the goal. This technology improves control of environmental impact by removing the risk of hydraulic fluid release, and personnel safety is improved with the removal of high pressure equipment and containment on topside facilities. Finally, electric technology demonstrates higher reliability compared to hydraulic systems and offers less complex subsea distribution and simpler hardware components. Electric Christmas trees have been successfully operating on two wells of the K5 field offshore Netherlands since 2008, and the electric downhole safety valve has been developed. Although K5F3 is a subsea well in a shallow-water environment, all components have been qualified for 3,000 m of water. In 2015, the global control system has been fully qualified and successfully tested through factory acceptance testing (FAT), extended factory acceptance testing (e-FAT), and site integration testing (SIT). The well was spudded early 2016, completed in June, and successfully put on stream in August. Electric control of wells is already taken into account for conceptual development studies and will become the base case for all of one operator's deep offshore projects when K5F3 demonstrates the efficiency of the technology.

An All-Electric Gate Valve Actuator for Subsea Production Control Systems, Part A: Prototype and Test

“…Compared with the hydraulic subsea gate valve actuator, the all-electric subsea gate valve actuator simplifies the structure of the actuator and its control system by eliminating hydraulic fluid and related high-pressure control equipment [34]. However, the design of the all-electric subsea gate valve actuator still needs to consider the functional requirements in terms of reliability, availability, safety, and operability in opening and closing the subsea gate valve [35,36].…”