With more than 400 subsea wells (and almost all classified as deep offshore), Total is one of the world’s biggest deepwater operators. Always ahead of the pack, in mid-2016 the Group unveiled the world’s first full electrically-controlled subsea well in the Dutch sector of the North Sea.
All-electric subsea wells are a real technological breakthrough for the oil industry. The result of nearly 15 years of R&D, they will considerably reduce development costs in deep offshore fields.
Offshore oil wells are currently controlled using hydraulic technology. In this process, a hydraulic fluid is routed from an onshore or offshore topside production center to a subsea well via dedicated umbilical pipes. This fluid is then circulated to activate the well’s hydraulic equipment: the manifolds, wellhead, and sub-surface safety valve.
All-electric subsea wells – simpler, more reliable...
The innovation consists of replacing this system with fully electrical infrastructure - wellhead, sub-surface safety valve and associated command system - which simplifies the entire assembly. All of the power needed to control the equipment is provided by an electricity cable instead of hydraulic pipes. Complex and entailing difficult and costly installation procedures, the umbilical pipes connecting the surface units to the subsea wells are no longer required.
The elimination of hydraulic fluid also reduces Total’s environmental impact, as there is no longer any risk of spillage into the natural environment. Furthermore, the removal of high-pressure equipment from the production centers increases the safety of staff and premises. With a simpler distribution system and components, the all-electric technology provides improved reliability over the conventional hydraulic system.
...and more cost-effective
A technological lever, all-electric control is also a substantial financial advantage. Replacing hydraulic pipes with an electricity cable over a distance of 30 km reduces costs by 15%. An electrical version of the well’s own equipment is expected to generate additional savings of 10%. Furthermore, all-electric control technology is suitable for the deployment of other innovations in subsea processes, especially for full subsea development plans targeted at low-cost scenarios. Compared with conventional solutions, these plans could help us reduce investment costs by 30-40% in future deep offshore developments.
The K5F-3 well: the precursor project
In early 2016, Total E&P Nederland drilled and completed the oil industry’s first-ever fully electric-controlled subsea well, dubbed the K5F-3 well. This world first is located in a deepwater field, but with equipment fully certified for operation in depths of up to 3,000 m.
The well’s entry into production in mid-2016 marked the end of nearly 15 years of R&D and multidisciplinary work, jointly spearheaded by the Group’s Drilling and Technology business lines. The K5F-3 well’s electrical production head was developed with the support of OneSubsea from the early 2000s, before being tested on two K5F wells from 2008. In parallel to this, the sub-surface safety valve was developed with the support of Halliburton. Total E&P R&D division designed the architecture for this solution, managed the research project, and instructed and co-financed the K5F-3 project. And finally, Total E&P Nederland played host to this industrial achievement for the benefit of all the Group’s subsidiaries operating in deepwater environments.
The all electrically-controlled subsea well technology was fully certified in 2015, notably obtaining the API14A for the sub-surface valve. It also successfully passed the FATs (Factory Acceptance Tests), e-FATs and SITs (System Integration Tests). In addition to this, Total is involved in certifying electrical control for the subsea process.
2017 will be the year our all-electric subsea well is validated on an industrial scale. Electrical control is already being routinely considered in our conceptual development studies, and it will become the standard model for all of our deep offshore projects once the K5F-3 well has fully demonstrated its effectiveness. A number of other oil companies and technology suppliers are keeping a close eye on the outcome of our project, as well as the development of associated technical components by our partners OneSubsea and Halliburton.
A precursor in the subsea industry, the Group is aiming to make all-electric subsea control an essential building block in its future full subsea developments.
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