Johan Sverdrup drilling platform installed

The 22,000-tonne topside for Equinor’s Johan Sverdrup drilling platform was lifted into position in one single lift by the Pioneering Spirit, the world’s biggest heavy-lift vessel, at the start of June. After initial preparations, the actual installation job took only three hours, making it possibly the fastest ever installation of a large, fully completed topside, according to Equinor (formerly called Statoil). Two of the four platforms planned for the first development phase are now in place.

Ståle Hanssen, Project Manager for the Johan Sverdrup jackets, installation and commissioning, describes the technology enabling single-lift installation of big platforms as a ‘game changer for the industry’. Up until now big topsides have been modular in design. No crane vessels have been able to lift more than 12,000 tonnes in one lift. The brand new lifting technology on Allseas’ Pioneering Spirit vessel, however, allows entire topsides of up to 48,000 tonnes to be lifted in one, single lift.

The technology was initially developed for the removal of scrapped platforms during decommissioning operations. Equinor is the first user of the technology for the installation of big, new topsides. This has allowed for great savings in the construction and installation phases, both in terms of manhours and costs, and, not least, reduces risks related to health, environment and safety.

‘Equinor and the Johan Sverdrup partnership, working closely with Allseas, have made a breakthrough for the industry here. The safety-, schedule- and cost-related benefits are substantial, and we expect that many others will follow suit,’ says Hanssen.

Pioneering Spirit will return to the Johan Sverdrup field in the spring of 2019, to install the last two topside structures in the first phase of the development, for the processing platform and the utility and accommodation platform.

Overall, the use of Pioneering Spirit will help cut one million manhours offshore, according to Equinor. This enabled the Johan Sverdrup partnership to deliver a plan for development and operation (PDO) for Phase 1 of the development which included an earlier start-up of the field by three to six months than would have been possible with the alternative topside installation solution. At the same time, this helped cut the estimated costs for the PDO by almost NKr1bn.

The drilling platform is due to become operational this autumn, tied back to eight wells pre-drilled by the Deepsea Atlantic semi-submersible in 2016. First oil is anticipated in late 2019.

Photo: Equinor Bo B Randulff