BP's Clair project marks a new chapter in the history of oil as it is the first project to establish a fixed platform using conventional North Sea technology to withstand the world's harshest sea environment.

Subject to North Atlantic swells, tides and currents, the Clair platform will sit in 460-ft (140-m) waters, close to the edge of the UK Continental Shelf and 47 miles (75 km) west of the Shetland Islands. It will have a design life of 25 years at that hostile location.
The jacket and platform, the initial means for tapping the estimated 4 billion bbl of oil in place, must provide that long service life and operational uptime without compromising on a strict environmental regime, requiring the facility to be as clean as possible with minimal environmental discharges. It's a tall order.
But above all, Clair will not be a high-cost project. BP made it clear when it embarked on the procurement process in 2001 that its facility would be built to Gulf of Mexico fabrication standards. This has translated into 30% savings over conventional platform construction costs. Phase one spending is put at about US $990 million (£650 million).
The jacket design features nothing particularly radical. It is a four-leg piled platform, and apart from the main integrated deck, the topsides process units will be little different from anything found on any other offshore installation.
So why is Clair so groundbreaking? In many ways it won't be. But the environmental hazards are considerable.
Environment
Once installed, the new platform will cope with a 100-year significant wave height of 56 ft (17.1 m) - 3 ft (0.9 m) less than the significant wave height in the Foinaven and Schiehallion areas farther west. Mean monthly significant wave heights are between 11 ft and 14.7 ft (3.5 m and 4.5 m) in the winter and 4.9 ft and 6.5 ft (1.5 m and 2 m) in the summer.
Severe winds throughout most of the year vary from moderate to strong breezes of 11 to 27 knots and strong winds exceeding 27 knots, according to the Clair environmental statement. Calm conditions (less than 1 knot) are rarely recorded.
Rain and snow will be regular visitors to the facility, too.
Two main tidal currents affect sea conditions in this location: the North Atlantic Slope current, traveling from southwest to northeast, just north of the Clair area; and a cold-water deep current, running in the opposite direction. Current speeds have been measured at between nearly 1 ft/s (0.23 m/s) at the surface and 6 in. per second (0.16 m/s) on the seabed.
Mustang Engineering in Houston, Texas, played a key part in the project providing front-end engineering and design (FEED) work worth about $5 million. The job involved 30 Mustang engineers and another 10 from parent company Wood Group, based in Aberdeen, Scotland, working to design a facility to contend with these conditions.
Mustang's challenge was to minimize the difficulties posed during the construction process so that the jacket and deck were built according to the original design without too many departures from initial drawings. That meant making it as simple and straightforward as possible, without "reinventing the wheel" as was so often said to be the case for recent new North Sea facilities. Although all North Sea installations have had to be robust, there has been a tendency to start from scratch each time a new one was built. BP hopes to move away from that philosophy.
"The challenge now is if we can actually get the benefit of that," the BP spokesman said.
At the time of the FEED contract award, Wood Group Chairman Sir Ian Wood said, "The Clair project provides exactly the right challenge for that vision: to permanently change the approach to new field developments on the UKCS by combining Mustang's design approach - fit-for-purpose, minimum design man hours and maximum standardization - with Wood Group's in-depth knowledge of UK government, HSA (health and safety awareness) and industry culture, programs and practices."
Bill Higgs, Mustang vice president, also expressed the desire to use the execution model employed on Clair elsewhere.
After the FEED was completed, Mustang and Wood Group Engineering took on the main platform design and engineering. The number of engineers grew to 150, and the project team moved from Houston to Aberdeen for the execution phase.
BP selected Amec in the United Kingdom to build the integrated deck for the Clair platform for a price tag quoted at $76.3 million (£50 million), while Aker Verdal in Norway won a $45.8 million (£30 million) deal to build the four-pile jacket. It will be built at Aker Verdal's fabrication yard 56 miles (90 km) north of Trondheim, Norway.
But beyond those two major contract decisions lie a raft of other procurement challenges about sourcing skid packages for the platform decks, valued at a further $38.1 million (£25 million) for the supply of topsides process equipment.
These packages are many and varied, but the requirements - from 8 tonnes to 800 tonnes - are not particularly radical. Of these various items, the largest are the gas compression module, a riser manifold and a production separator, all out to bid earlier this year.
Many other items are needed as well, and BP has established a detailed list. It also has publicly indicated which contractors are bidding for them - which is unprecedented.
When announcing the contracts for Amec and Aker Verdal, Scott Urban, BP's group vice president for northwest Europe, said, "Our tendering strategy has enabled us to award these contracts in both cases to the most competitive bidder that met our safety and technical requirements." The statement was a clear signal that safety and environmental performance were as highly regarded as any economic bid price in the tendering process.
Amec considers its lost-time accident record at its Teesside fabrication facility in Wallsend, England, a big factor in its success for the Clair contract. It will build a deck that is expected to weigh 10,500 tonnes once complete, allowing a single-lift installation.
Aker Verdal's jacket will comprise an 8,500-tonne cross-braced, four-leg support structure with 14 piles weighing another 4,300 tonnes. Again, it will be possible to install the jacket in a single lift. Once built, this new structure will be placed over a previous Clair appraisal well, 206/8-10z.
The Clair jacket will be 540 ft (165 m) tall with a base footprint of 164 ft by 128 ft (50 m by 45 m). The main support deck will be 114 ft by 65 ft (35 m by 20 m).
Deck and jacket are due for delivery by April 2004 for installation the same year. It will be the 29th jacket built at Aker Verdal, where four others - Shell's Goldeneye and Norway's Kvitebjørn, Valhall and Grane - are under construction.
Workers will apply a corrosion-resistant coating to the jacket, which also will feature sacrificial anodes, to mitigate the effects of wind and wave action on the steel.
A preinstalled positioning template and docking piles will ensure accurate alignment for the jacket when it goes in. The jacket will use foundation skirt piles with four 8-ft (2.4-m) piles per jacket leg, to be driven into the seabed some 82 ft to 98 ft (25 m to 30 m). Saipem will install the jacket and topsides.
Clair's platform topsides will feature a main, production and cellar deck to accommodate drilling and processing of produced fluids. Additional facilities will handle offshore power generation, water and cuttings reinjection and surplus gas disposal and flare gas recovery. It also will feature 28 well slots. Process equipment will handle up to 67,000 b/d of 23° API crude and a gas throughput of 21.7 MMcf/d. Plateau production from the first phase is expected to be 60,000 b/d of oil and 15 MMcf/d of gas.
Equipment specifications include the ability to handle 100,000 b/d of water since "a major increase" in water production is anticipated early in the project. Produced water will have to be processed to reduce oil content below a 30-ppm standard.
Twenty-three wells plus the 206/8-10z slot - 15 producers, eight water injectors and one cuttings reinjection well - are required in the project's first phase.
Dry trees round out the platform design. Again, this is not particularly radical, but it reflects the requirements the reservoir places on the platform design. High-angle and horizontal production wells are part of the project design, since large stepouts from the platform are required to access reserves.
"Early in the decision-making process, it was recognized that because of the nature of the reservoir, there will be the need for frequent well intervention, creating a strong demand for dry rather than wet trees (in other words, platform wells rather than subsea development wells)," BP said. Coiled tubing and electric slickline equipment is specified to allow for such well intervention operations.
Crude oil will be exported via a 66-mile (106-km) line to the Sullom Voe oil terminal in the Shetlands, converging with the route of the Magnus Enhanced Oil Recovery (MEOR) pipeline - from Schiehallion and Foinaven fields - at a point 25 miles (40 km) west of the Shetlands. From there, the Clair and MEOR lines run parallel into Sullom Voe.
More to come
Designing, building and installing the new platform, and then beginning production by late 2004, will be only the first chapter in the Clair story.
BP and its partners intend to look hard at tapping the rest of this vast reservoir.
"Appraisal of the remaining area of the field referred to as greater Clair has shown considerably greater oil reserves (2.25 billion bbl)," BP said in its environmental statement. "The Ridge segments of the reservoir are potentially the most prospective, but information on greater Clair is limited due to poorer seismic quality and limited status and well test data. Without further appraisal drilling, there is a large amount of uncertainty and hence risk associated with development beyond phase one."
However, further work is intended. "Continued appraisal of greater Clair with the objective of additional development phases forms a fundamental part of the Clair partnership's long-term strategy for full field development. This will involve seismic acquisition and two or more appraisal wells aimed at testing reservoir productivity. Dependent on the success of this activity, a phase two project could follow."
A subsea wellhead for the Ridge reservoir area is moot if this is deemed necessary later.
Clair is a big prize worth catching - but only if the elements allow it.

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