Multi-role drilling unit configured for long-term Gulf assignment

Deepwater drilling is also the main mode planned for Statoil's latest multipurpose shuttle tanker (MST). This 97,500dwt newbuild is currently under construction at Astilleros Españoles' Puerto Real yard near C diz. Its first job will be a five-year drilling contract from Shell Deepwater Development in the Gulf of Mexico, starting in 1999.

Deepwater drilling is also the main mode planned for Statoil's latest multipurpose shuttle tanker (MST). This 97,500dwt newbuild is currently under construction at Astilleros Españoles' Puerto Real yard near C diz. Its first job will be a five-year drilling contract from Shell Deepwater Development in the Gulf of Mexico, starting in 1999.

Statoil Shipping and Maritime Technology will own the vessel while partner Smedvig manages drilling services and operation of the vessel. The 253 meter long unit will incorporate a 12.5 x 19.2m moonpool, and will be able to work in water depths down to 10,000ft. Oil storage capacity will be 81,200 cu m, with accommodation for 120 crew members.

This will be the fourth MST in Statoil's pool and the first to operate in the Gulf. Long-term, it could be modified and redeployed as an FPSO, FSO or shuttle tanker - not quite attaining the industry's goal of an integrated FDPSO all at once, but the next best thing.

According to Astilleros Españoles' Juan Carlos Pérez, Statoil first considered the drillship potential two years ago when the MST concept was getting off the ground. Initially, Statoil envisaged an advanced shuttle tanker operating through submerged turret loading, capable of switching without too much strain to an FPSO through installation of modularized plant. Size would be determined by the reservoir's characteristics - depending on a production rate of, say, 40,000 or 60,000b/d, modules could be added accordingly.

Having contracted Samsung to build three MSTs in this vein, it then dawned on Statoil that the production mode might not be necessary for such large vessels. Thoughts turned instead to implanting a drilling capability, putting a moonpool in the center with a drilling substructure on top - but maintaining the hold open for submerged turret loading at a later date.

Following discussions with Statoil, Astilleros was awarded the construction project for the fourth MST. Puerto Real is building the hull, but Statoil is keeping its options open on the topsides fabrication and installation award. Pérez's view is that these tasks, plus hull construction, are best handled at the same yard to save time and costs, as was demonstrated by the Texaco Captain FPSO alliance.

As for the future, says Pérez, "combining drilling and production in this way is a step forward in the market. And it is another clear indication that drilling will continue to go as we predicted to very deep waters, as opposed to using semis with tremendous amounts of moorings".

The MST contract is the continuation of a long relationship between the two companies. Earlier this year Statoil awarded Astilleros Españoles a $260 million contract to build three new shuttle tankers, destined to work on Norway's Haltenbanken fields. Construction will be shared between Puerto Real and another of the group's yards in Sestao, northern Spain.

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