Mantyluoto facilities with Exxon Hoover-Diana DDCV. Aker at Mantyluoto hopes soon to be fabricating a new series of truss spars for projects in the Gulf of Mexico and West Africa.
Aker Rauma Offshore's yard at Mantyluoto in Pori, Finland has been relatively quiet this past year, following completion of the 37-meter diameter, 32,000 ton deep-draft caisson vessel for Exxon's Diana-Hoover field in the Gulf of Mexico. Fabrication of some Ro-Ro passenger ferry sections for its sister company, Aker Finnyards, has been the only work of any significance.
However, there are signs that the production line for the structures more commonly known as spars will soon be back in business. Parent company, Aker Maritime, has moved to consolidate its position in the deepwater sector of the market, as development activity recovers in the wake of what is now seen by most industry analysts as a sustainable revival in the price of oil.
Aker Maritime has designed its latest spar variant, the pipe spar, to target the deep water market in the Caspian.
Aker Maritime and J Ray McDermott recently decided to dissolve their spar platform alliance, which had been in operation since 1996, and had been responsible for delivering Chevron's Genesis spar platform. The breakup appears to have been as amicable as any could be, with announcements to the effect that the two companies would in future compete on some projects, but continue to cooperate where the client's preferences rendered it appropriate.
Aker Maritime has been first to stake its claim in the spar market, and from what has been said, its commitment to spar technology will, if anything, only become firmer. Reports indicate that the majority of staff from the former joint companies, Spars International and Deep Oil Technology, have joined Aker Maritime's Engineering and Technology Group in Houston.
The company has reorganized, forming two new departments, Riser Technology & Well Systems and Deepwater Solutions R&D, and there is talk of expansion later in the year. This is good news for Aker Rauma at Mantyluoto, which essentially forms the fabrication arm of the spar business.
Two with McDermott
The Murmanskaja drilling rig is capable of drilling in Arctic conditions. It is the latest in a long line of upgrades carried out by Aker Rauma in partnership with local Russian yards.
Jarmo Eerola, Sales Manager of Aker Rauma, reported that front-end engineering was being undertaken both in Houston and Pori on four spar projects in the Gulf of Mexico - two still in conjunction with J Ray McDermott. "The outlook is very promising," said Eerola. "We are hoping for a positive announcement on one of the projects very soon. Assuming we get the go-ahead, we could be looking to begin fabrication around the middle of the year at the Mantyluoto yard." Eerola is hopeful that the other projects will ultimately come forward. Given the capacity of the Mantyluoto facility and the likely timing of the various projects, he is confident there will be no difficulty in meeting the consequent fabrication schedules.
There is also promise of business in West Africa. Conceptual studies are underway on two potential spar projects, neither of which involves McDermott. Aker Maritime's focus in this region was recently sharpened by the opening of an engineering office in Luanda, Angola.
What have become known as truss spars are being considered for all the new projects. These have been the subject of considerable study over the past year or two, on the basis of their reduced weight and therefore lower cost, but so far, none have been built. Chances are this will change in the near future.
All three spar hulls so far constructed at Mantyluoto have been to the conventional design - cylindrical for their full length. The truss spar is different in having three distinct parts:
- Cylindrical top section which provides buoyancy
- Open truss section, which is a relatively lightweight, space frame structure
- Lower "bottle-leg" or tank section designed to hold the required fixed ballast.
Eerola was reluctant to discuss details of any of the new potential projects. However, papers published previously by Deep Oil Technology have described a variety of wellhead truss spar platforms for intended use in West Africa.
The designs have been based on a common 32-meter diameter hull but capable of supporting deck loads between 4,000 tons and 13,000 tons, and production rates up to 120,000 b/b of oil and 45 MMcf/d of gas. The wellhead truss spars have dry trees, receive production via top-tensioned risers, and export through a series of steel catenary risers to a host platform. Having minimal processing equipment, they are designed for unmanned operation.
Pipe spar concept
In another off-shoot of the spar concept, Aker Maritime has launched the "pipe spar," specifically with Aker Rauma's business connections in the Caspian in mind. Nicknamed the Caspar, the spar platform hull, which is formed from a series of pipes, is designed for use in depths of up to 1,000 meters in the Caspian Sea.
The idea is that the hull would be fabricated at Aker Mantyluoto in relatively small but complete sections, so that it could be transported easily through the Volga River and canal system into the Caspian for final assembly. "The design allows for most of the fabrication work to be undertaken at Mantyluoto and eases the demands on the fabrication capacity in the Caspian yards," explained Eerola. Aker Maritime has a series of long-standing alliances in place with various fabrication yards in the region.
Eerola hopes that the Caspar will open up a new phase of development in the Caspian Sea. "The semisubmersibles already in widespread use in the Caspian can be upgraded to operate at depths up to about 500 meters. "The spar-based structure will provide new options for the operators there," he said.
Like the established spars, this new design would be built with both drilling and production facilities. However, it is envisaged that the drilling rig could be removed, once into the production phase to permit heavier deck payloads.
Apparently, several studies have been carried out for potential customers in the region. Realistically, given the pace of developments in the region, it will be 2001 before construction is even considered.
Continued rig business
Aker Rauma Offshore has been in operation since 1972 and rig construction and upgrading has always been a major business line. In recent years, it has also delivered a number of successful projects of this kind in collaboration with various yards in the Caspian region. Aker Rauma undertakes the engineering and procurement and provides site supervision and fabrication management expertise from Finland to the local yard.
In July last year, it delivered the Sunkar drilling barge from the Morskoi Zavod yard in Astrakhan. This is now working for the OKIOC consortium of oil companies in the ice-locked northern Caspian. The Astra rig was also delivered last year from the Krassnye Barrikady yard in Astrakhan and has been operating successfully for LUKoil.
The latest in a line of such projects is the upgrade of the 1988-built Murmanskaja jackup rig for the Russian AMNGR consortium at a yard in Murmansk. This is expected to be completed in June. The rig will return to its former operating theatre in Arctic waters.
The company is also bidding for the upgrading of the Caspian Drilling Company's Dada Gorgud semisubmersible drilling rig, which it originally built in 1978. The rig is reported to be earmarked to work for BP Amoco in the Azeri field. At one time, it was thought this would entail considerable work but the scope of the modifications is unlikely to match the early expectations.