Feature 3 | DEEPWATER & ULTRA-DEEPWATER OPERATIONS
Rising to the challenge
Recent work by Harris Pye to improve the stability of Seadrill’s ultra- deepwater semisubmersible West Pegasus ended up being more than the group bargained for, writes Nicola Stuart.
T
he West Pegasus ultra-deepwater semi-submersible,
owned by Seadrill, has recently undergone
extensive work to prepare the rig ahead of its five-year contract with Mexico’s Pemex. The Harris Pye Group announced the completion of a six-week contract for work on West Pegasus at the end of October. Te final contract was valued at US$4.3 million. Initially, Harris Pye had only been
contracted to fit four 72tonne column blisters onto the rig’s legs. Tese stiffened rectangular steel boxes, or blisters, are fitted to the columns of a rig in order to proportionally increase the water plane to the metacentric height (GM); this ultimately improves the stability of the vessel, explains Harris Pye’s group technical director, Chris David. However, he adds: “Once on board it
became obvious there was more work to be undertaken to equip West Pegasus for its five-year contract with Pemex, and our role was greatly extended.” David goes on to explain: “Our extended
role on board the West Pegasus encompassed the supply of tow bridle tuggers and working
platforms; installation of transformers and associated power supplies; modifications to lighting circuits; mudroom stairway installation; new shaker room platform; sea water pipework to RO system; helideck and accommodation walkways; helideck lighting; welding the point ring main; work in the mud treatment room; and installation of miscellaneous lighting and cabling. Once on board the strengths of our team were fully maximised on a variety of tasks.” Projects such as this are oſten necessary
in keeping with the changing requirements of the operator during oil field development, and each one is different. According to David: “Different oil field drilling projects require different technology and approach. Invariably, the client’s requirements and future expansion upgrades dictate what upgrades will be required at the oil field. At any one time we [Harris Pye] have two or three projects on the go.” Te column blister contract encompassed
the supply of a complete project team; and the design, fabrication and installation of all miscellaneous steelwork to assist
in the lifting and fixing of the blisters. “The lifting operation involved some highly innovative solutions,” says David. Supplies for the contract included 4000m of scaffolding; painting repairs; all tools, equipment and consumables including gases; and a substantial amount of freight. Full documentation on quality control and quality assurance was also included in the contract. “We had to design and construct special
liſting structures to assist the liſting of the blisters into position due to the position of the columns as they are not readily accessible by normal floating cranes,” explains David. Five out of six weeks of the contract were
spent actually on the rig in Curacao and involved a workforce of 115. Te column blisters were fitted first before moving on to the extended renovation and refurbishment. David notes that among the main challenges associated with carrying out this kind of work at sea is that of logistics. He is keen to note that “accommodation for workmen and the safety of workmen is of paramount importance”. OMT
P10000 proves popular choice
GustoMSC’s dynamically positioned drillship design, the P10000, is proving a popular choice among operators in the midst of enhancing their deepwater fleets.
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xploration in onshore and shallow water oil fields is on the decline as reserves begin to deplete, which is
leading many companies to refocus their operations on fields situated in deeper waters. High drilling activity rates in areas such as offshore Brazil, and interest in emerging areas such as offshore West Africa, Indonesia, the Black Sea, India and eastern Africa is driving demand for newbuild deepwater and ultra-deepwater drilling capability. As operators invest in harnessing the potential of deepwater and ultra-deepwater,
they are moving to enhance their deepwater fleets to cope with demand. This has seen Netherlands-based GustoMSC recently secure an order for the fourteenth ultra-deepwater drillship of its P10000 design since the first vessel, Deepwater Champion, was delivered to Transocean at the end of 2010. Deepwater Champion was constructed in cooperation with Hyundai Heavy Industries (HHI), South Korea. The latest vessel on order, announced
in November, will be the third such drillship for Rowan Companies after
the company exercised an option for its third vessel of the class. Also to be built at HHI’s Korean shipyard, the new drillship will be delivered in the fourth quarter of 2014. Te P10000 design was developed using
experience gained from GustoMSC’s Pelican class, the first-ever dynamically positioned drillship, with the design coming to maturity between 2000 and 2010. P10000 is a fully integrated drillship design conforming to the requirements for a sixth generation, and beyond, rig. It is designed for operation
Offshore Marine Technology 4th Quarter 2011
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