Aqualis Offshore Completes Jacket Installation
Marine and offshore engineering consultancy Aqualis Offshore has completed the offshore installation engineering of an 1,800t steel jacket structure offshore Bahrain as part of the Bahrain LNG Import Terminal.
Aqualis Offshore delivered the project in cooperation with APMC, who were in charge of the transportation and installation contract on behalf of its EPC contractor client, GS E&C. Aqualis Offshore was contracted by GS E&C to provide loadout, transport, and offshore installation of the jacket. Aqualis Offshore’s scope of work provided full engineering services related to the loadout, transportation, float off operation, towing, positioning, lowering to the seabed, and buoyancy tank removal, including all marine procedures. The offshore installation was executed in May 2018. An innovative approach for jacket installation in shallow water was applied by using engineering buoyancy tanks to allow the jacket structure to be floated-off the transport vessel, towed to site, and lowered to the seabed through ballasting. This negated the need for mobilising any large installation crane vessel.
“The jacket, with three of six main piles slotted into the jacket legs, and its buoyancy tanks were loaded out onto pre-installed grillages on the submersible heavy lift vessel using trailers,” says Mr Phil Lenox, Director – Asia Pacific, Aqualis Offshore. The Wish Way heavy lift vessel was utilised to transport the jacket from SKMT (Samkang M&T) in Goseong Yard, South Korea to its destination at its final location offshore Bahrain at a 20m water depth. “On arrival, the heavy lift vessel was ballasted down for the jacket to be floated off at a suitable nearby site and towed 5km to the installation location in shallow water. Following positioning between the breakwater and jetty structure, the buoyancy tanks were ballasted to lower the jacket to the seabed. After driving the main piles, the buoyancy tanks were removed from the jacket structure by releasing connecting pins and deballasting the tanks for recovery,” adds Lenox.