Tim Skelton looks at the Statoil-backed Cap-X system, designed to usher in new subsea standardisation at the NOC’s Bauge and Njord fields
In March this year Statoil submitted its 20 billion kroner (US$2.3 billion) plan for developing the new Bauge field and rebooting the existing Njord field, both located in the Norwegian Sea. Speaking on behalf of project partners that include Engie E&P, DEA Norge and Faroe Petroleum, the company said a combination of operational efficiency improvements and new technology developments had helped shape the plan.
The most critical of these would appear to be the recently developed Cap-X system, which is designed to bring standardisation to the industry and is being put into use here for the first time.
Statoil’s original expectation for Njord was that it would have been scheduled for decommissioning in 2013. But thanks to operational efficiencies brought about by, among other things, greater co-operation between project partners and with suppliers, the new plan will now extend that field’s production life until around 2040.
In order to keep it operating efficiently and profitably for a further two decades, both the existing Njord A production platform and the Njord Bravo floating storage and offloading vessel (FSO) will be upgraded in order to increase recovery rates and extract more of the remaining resources from Njord, as well as from the nearby Hyme field. Between them these two fields are estimated still to contain around 175 million recoverable boe.
Work at Njord A will also facilitate the tie-back of the new Bauge field development, which is located just four km from Hyme and some 16 km northeast of the platform. The first proven reserves at Bauge were discovered in October 2013, and its recoverable resources have since been estimated to be around 73 million boe. The field development concept includes one subsea template, two oil producers and one water injector. Tying Bauge in to Njord A will itself increase the life of Njord by three years, the project partners say.
Cap-X The development at Bauge is significant, as it will see the first deployment of Statoil’s next-generation Cap-X subsea production technology, which it claims is cheaper both to produce and to install than other systems.
The technology was originally unveiled last year at the Barents Sea Conference. It builds on well-proven concepts by putting them together in new ways. Its most notable impact will be to reduce the subsea footprint by around 75%. Conventional templates have a footprint greater than 20m by 20m, but Cap-X works on an average area of around 10m by 10m.
The Cap-X seabed foundation uses a suction anchor technology that was originally developed jointly by Statoil, Royal Dutch Shell and the Norwegian Geotechnical Institute. The anchor is made from steel, with a fibreglass housing comprising a skirt and cap fixed on top. This superstructure then forms a compact protective casing capable of housing standard subsea equipment such as Christmas tree systems.
The casing has a streamlined square-based pyramidal shape that will, among other things, help to reduce the risk of potential damage caused by the snagging of trawler nets dragged by vessels passing on the surface.
Being only one-quarter the size of other subsea templates in current usage will enable more operations to be conducted from a mobile vessel instead of from a fixed rig, Statoil says. The longer-term plan is to use Cap-X as a practical solution for helping to commercialise potential resources in the Barents Sea, as well as in other areas that have shallow reservoirs. This initial rollout in the less harsh environment of the Norwegian Sea will help to prove its value in the field.
The new standard The ultimate goal is to bring about efficiencies, and hence improve profitability, by standardising all subsea structures. Statoil says the Cap-X housing can be produced more simply and in a shorter timeframe by many different suppliers, offering the potential for more efficient and more localised production at sites closer to the point of use. This combination of smaller size and reduced distances makes it more easily transportable, and moves much more of the installation process from rig to ship.
According to Cap-X inventor Kjell Einar Ellingsen, this will save rig days and marine installation costs, by facilitating faster operations and enabling the use of simpler vessels. The possibility of drilling single wells also allows for more flexibility in terms of seabed positioning, providing more optimal drainage of the reservoir, he told the Norwegian industry website petro.no.
Perhaps most importantly, at least as far as Statoil and its partner’s accountants will be concerned, is that the company expects Cap-X’s design to cut overall costs by as much as 30% compared to conventional subsea installations. The part-state-owned oil major has called its design the “next generation of subsea solutions,” and says it brings the oil and gas industry a step closer to the ideal – and indeed long-promised – solution of “plug in and play” equipment for the seabed.
Both the rebooted Njord and Bauge developments are scheduled to come on stream at the end of 2020, and they will bring a welcome boost to the industry in mid-Norway and on the Norwegian Continental Shelf (NCS) as a whole. The decision to go ahead with the confidence of making both fields pay marks a refreshing change from recent years when new projects in the region have been squeezed by high up-front and operational costs.
The lessons learned can also be applied to other Statoil fields, which it hopes will herald the arrival of a new era of low-cost profitability. “With new technology, project improvements and close co-operation with the partners and supply industry, we now see opportunities to create considerable value for another 20 years,” executive vice president for Technology, Projects and Drilling Margareth Øvrum said in March.