Bells and whistles

Odfjell Drilling’s Deepsea Aberdeen has all the bells and whistles for working west of Shetland. Elaine Maslin takes a look.

Deepsea Aberdeen working west of Sheltand. Photo from Odfjell Drilling.

It’s new, bespoke, highly automated, multifunctional and multipurpose. No, it’s not the latest Bond Aston Martin, it’s Odfjell Drilling’s sixth generation dual-derrick semisubmersible drilling rig Deepsea Aberdeen.

The unit, Odfjell’s latest newbuild, started working for BP on its West of Shetland assets, including the Quad 204 redevelopment, on the UK Continental Shelf on 21 April 2015. Under Odfjell’s largest ever contract, the unit is on a seven-year drilling program for BP and its co-venturers, starting with two production wells and a water injector on the Loyal field, which is part of the Quad 204 redevelopment, before moving to the Schiehallion field, also part of Quad 204 (OE: September 2015, June 2015, July 2013).

The new bespoke unit, capable of drilling in up to 3000m water depth, has dual derrick capacity for dual operation, fully automated “green rig” with no-leak design, and is fitted out in order to work in environments as harsh as the West of Shetland and the Arctic.

Despite hiccups during the construction of the rig setting back the initial delivery date – it sank at its wharf late 2013 after water ingress, and then part of a BOP was damaged during sea trials – she’s a highly advanced unit, says proud rig manager Stein Harald Nielsen, who has been in charge of the Deepsea Aberdeen from four months before Odfjell took delivery of the unit from Daewoo Shipbuilding & Marine Engineering (DSME) in South Korea.

“It is probably the most advanced rig in the world,” he says. “The system and equipment is really state of the art. We do not have any personnel near the rig floor, everything we do is more operated and that is something new for many of the staff.”

Deepsea Aberdeen is the latest in a string of GVA 7500 (enhanced) harsh environment design rigs Odfjell has had built, following on from sister rigs Deepsea Stavanger and Deepsea Atlantic, also built at DSME.

But, Deepsea Aberdeen is the cream of the crop, having had extra bells and whistles added to meet long-term customer BP’s specifications. This includes the dual derrick capacity (1000-ton and 500-ton), with a main and auxiliary work center and two (HPS-1000) top drives instead of traveling blocks, for simultaneous operations, and dual and single active heave compensating drawworks for increased performance, efficiency, safety and redundancy. The drawworks, mud pumps, and HPS-1000 top drives were supplied by NOV in Norway.

Being able to perform dual operations is a real advantage, Nielsen says, especially when it comes to efficiency and so far the results have been good. “It obviously takes some time – you have to crawl before you can walk – but the crew has been fantastic and we have seen some really efficient drilling operations in the 6-7 months we have been here,” he says.

The Deepsea Aberdeen is also equipped with a full conventional mooring spread for operations in 70-500m water depth, but can also work in up to 3000m (10,000ft) water depth on DP. Its 7500-tonne loading capacity in all operating conditions enables efficiency, with a reduced need for re-supply. It can also be fully winterized for working in Arctic conditions.

The rig, classified by DNV GL and able to accommodate up to 158 people, has two BOPs, one six ram electric and a five-ram hydraulic MUX BOP, both 18-3/4in and 15,000psi-rated.

The green rig design concept means any leak paths are fully enclosed so nothing can leak into the environment. It has full a dual mud system for reduced contamination and separate completion fluid system. It has four, high-pressure, high-capacity, mud pumps (14-P-220, 7500psi), and six high-capacity shakers. There is also a large set back capacity for drillpipe and casing.

If you want to see more, the rig even has its own Facebook page – something Bond’s latest Aston Martin doesn’t have either.