The steel jacket for the Statoil-operated Mariner field on the UK Continental shelf (UKCS) has now been safely placed on the seabed in the field.
Following the sailaway from the Dragados Offshore yard in Cadiz, Spain on August 10, the Mariner jacket recently spent a week in the sheltered Boknafjorden near Stavanger, while waiting for the heavy lift vessel Saipem 7000 to arrive at the field.
In the early hours of Sunday 30 August the “Skandi Iceman” vessel, towing the S44 barge with the jacket, and the heavy lift vessel were in place in the Mariner field, approximately 150 kilometres east of Shetland. The operation is also assisted by three support tugs and a safety vessel.
At 20:25 Sunday night, the jacket was successfully launched from the barge.
During the early hours of Monday, August 31, the jacket was hooked up to the cranes, up-ended and placed on its permanent location.
The tug “Boulder”, towing the Wagenburg 9 barge with the piles, is expected to arrive on the field today. A total of 24 piles will be driven into the seabed to secure the platform jacket. Each pile is 65 metres long with a weight of 250 to 300 tonnes.
The remaining installation activities are expected to continue for another 10-14 days. 134 metres high and with a footprint of 88 x 62 metres, the Mariner sub structure is the largest steel jacket ever built for a Statoil project. The weight at load-out was 22,400 tonnes including floatation tanks and rigging.