Deep Offshore: the First All-Electric Subsea Well
Getting a head start on the industry, Total launched the world’s first all-electric subsea pilot well in 2016. The result of over ten years of R&D, this technology will be one of the key solutions used to lower deep offshore project development costs.
Reducing the cost of subsea tie-backs
Deep offshore: technical responses to new challenges
Since summer 2016, a decisive step for the future of deep offshore has been taken with the commissioning of the oil industry’s first all-electric subsea well. Total’s position as a pioneer in this technology is attributable to the research launched by the Group more than ten years ago regarding deep offshore architectures that would lower subsea tie-back costs.
The solution was to simplify, or even eliminate, umbilicals between subsea production systems and processing units on floating or onshore facilities. To make this possible, the electrical control of wells and, more generally, of subsea production systems, was one of the technological barriers that had to be overcome as it would significantly reduce the need for hydraulic lines in the umbilicals.
For several years, we were the only ones investing in the development of the electrical control of subsea wells. Nevertheless, we never questioned this decision, which has now been vindicated by the industry’s recent surge in interest in this technology.
K5F, a pioneering subsea project
Our electrically-driven subsea industrial pilot well was commissioned in mid-2016 to undergo tests, which will last 12 to 18 months, in the K5F gas field of the Dutch North Sea. This is the industry’s first project to have taken up the challenge of implementing an all-electric subsea production system, which was designed in 2004.
In 2008, the field’s first two wells (K5F-1 and K5F-2) would have paved the way for the world’s first electrically-driven Christmas trees (e-Xmas trees), developed with OneSubsea. However, as there was no electric DownHole Safety Valve (e-DHSV) on the market at that time, the conventional hydraulic control system had to be retained for this equipment.
We have since filled this gap and developed, in partnership with Halliburton, an e-DHSV that has the technological readiness level required for it to be fitted to a new pilot well. Thereby, K5F-3 now incorporates three devices that will make it the world’s first true all-electric subsea well: an e-Xmas tree, an e-DHSV and an e-SCM (electric Subsea Control Module), which manages interactions between the two other devices.
The well’s power supply and control will be managed from an inhabited platform (K6P/C) through an 18-km umbilical. High-voltage (3,000 V) low-intensity (4 A) direct current carried by the umbilical will be converted, on the seabed, by a PRCM (Power Regulator and Control Module) into a lower voltage (300 V) and higher intensity (40 A) current to power the well’s electrical equipment actuators.
ALL-ELECTRIC SUBSEA WELL TECHNOLOGY – ALREADY A PART OF PROJECTS CURRENTLY UNDER CONSTRUCTION
We have great confidence in this pilot well. The electrical actuators of the trees and of the e-SCM, in operation since 2008, have proven that they are reliable. The difficulties encountered, inherent to any pilot project, have been overcome and improvements have been made. The e-DHSV, which will complete the K5F-3 well’s all-electric system, has been intensively tested and fully complies with standard API14A.
By 2017, the all-electric subsea well will have been demonstrated on an industrial scale. This concept already forms part of our current projects, particularly the development of satellite fields around existing deep offshore production sites off the coast of Angola. Starting next year, it will constitute the base case for our offshore development projects that reach a depth of up to 3,000 m.
This technology, whose primary benefit is the reduction of costs, has matured just at the right time given the difficult environment currently affecting the industry. It also promises more competitive development projects, both for our clients and our partners, and economical access to new reserves that are further away or at a greater depth.