CIS Group completes subsea piling operation in North Sea
GREAT YARMOUTH, United Kingdom -- Conductor Installation Services (CIS) has completed a subsea piling operation for Subsea 7 in the UK North Sea.
CIS used its remotely-operated Subsea Piling System, which makes it possible to drive piles as large as 42 in. in diameter, in water depths to 300 m. The operation was executed as part of the Cladhan Field development, located approximately 100 km northeast of the Shetland Islands.
The development will eventually connect Cladhan field, via a new subsea tieback, to the Tern Alpha oil production platform, which lies 17.5 km northeast of Cladhan field. In preparation for the tieback, CIS drove piles to secure a subsea manifold to the seabed on Cladhan field.
Rapid response
Work was carried out as a result of a contract awarded to CIS by Subsea 7 on April 9. Following preparation and testing of all equipment at its base in Great Yarmouth, UK, CIS transported it to the port of Nigg in Invergordon, Scotland.
On April 28, it was loaded onto the support vessel, from which CIS would carry out the subsea piling operation remotely. In the early hours of April 30, the crew set sail for Cladhan field to the site of the subsea pile-driving operation.
Subsea piles driven in just 4 hours
The subsea operation was commenced and completed on May 2. CIS worked in a maximum water depth of 160 m to drive four 24-in. pipeline end manifold (PLEM) piles.
Each pile was driven to its target depth of 12 m. The piles driven measured 16.5 m from the Seven Falcon vessel, ultimately reaching a depth of 12 m below the mudline of the seafloor. CIS completed the entire subsea driving operation in well under four hours.
