During 2002 Oil States MCS Limited (OSMCS) were contracted by Heerema Marine Contractors Nederland BV to provide equipment and personnel for performing the Abrasive Water Jet Cutting operations on the Frøy Platform abandonment project in the Norwegian sector of the North Sea. OSMCS were contracted to cut the following tubulars:
• 8 x 2418mm OD x 70mm wt skirt piles above the
guide cone, to facilitate pile stick-up removal
• 8 x 2418mm OD x 90mm wt skirt piles 1.5 meters
below the mean seabed level
• 2 x 1524mm OD x 70mm wt docking piles 1.5
meters below the mean seabed level
• 3 x 762mm OD x 20mm support piles 1.5 meters
below the mean seabed level
• 2 x 1000 bar Abrasive Water Jet Cutting systems
• 2 x 72" - 108" Internal Cutting Manipulators (ICMs)
for the 2438mm pile cuts
• 2 x 30" - 60" ICM’s for the 1524mm and 762 mm
pile cuts
The Frøy platform consisted of a single modular topside and a four-legged jacket secured by eight 2438mm (96") skirt piles. Situated beneath the jacket was a drilling template secured by three 762mm (30") piles, the template also contained guides through which the two 1524mm (60") jacket docking piles had been driven.
The removal of the jacket was carried out using Heerema’s SSCV Thialf during the summer of 2002, the operations being conducted in two phases.
Phase 2A operations were carried out during the period 24th June 2002 to 12th July 2002, which saw the removal of the eight pile stick-ups and the cutting of four skirt piles below the mudline.
Phase 2B operations were then carried out during the period 3rd September to 15th September. During this phase the four remaining skirt pile cuts and all cuts associated with the template were carried out. The template piles only became accessible once the jacket had been lifted.
Both the jacket and template were successfully lifted from the seabed at the first attempt.
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Oil States Industries, Inc.
Oil States International, Inc.