Statoil begins installation work on Asgard subsea compression modules

Statoil ASA has started installation of the modules comprising the subsea gas compression plant for Asgard field in the Norwegian Sea. A total of 22 modules will be installed and connected, forming two 1,500-tonne compressor trains.

The modules over the summer will be laid in place in a large subsea frame that was installed 2 years ago (OGJ Online, June 13, 2013). The newly rebuilt North Sea Giant vessel is carrying out installation work.

The modules comprising plant vary in size, with the smallest installed via the vessel’s “moonpool,” a large opening in the bottom of the hull through which modules weighing as much as 70 tonnes are lowered.

The larger modules are installed by the North Sea Giant’s crane system, which has been modified to incorporate a special handling system. The system is designed to carry up to 420 tonnes and operate in up to 9-m-high waves. Each module is guided into place with a remotely operate underwater vehicle and cables.

All modules are provisionally stored at Vestbase in Kristiansund, Norway, where they’re shipped out following commissioning and testing in Egersund. Statoil notes that the installation sequence has been planned so that start-up work can be carried out on the first compressor train while installation work continues on modules for the second train.

Conducted in 300 m of water, the project will result in additional production of 282 million bbl from the field, the company says. Last year, a contract was given to Technip SA for intervention services on the compression stations (OGJ Online, Feb. 11, 2014).