Second nitrox diving project for Premier Oil.

IRM campaign to help extend the life of assets in the UK Central North Sea.

JF Subtech* provided a nitrox diving spread utilising gravity-based launch and recovery systems (LARS) installed on the Balmoral floating production vessel (FPV) in blocks 16/21a and 16/21b, approximately 200km northeast of Aberdeen.

The company utilised a Zone 2-rated nitrox system directly from the customer’s production asset, providing a cost-effective alternative, and the use of nitrox significantly extended dive times and increased productivity while simultaneously reducing manning levels

On the back of a successful campaign with Premier performed late last year, JFMS supplied a dive crew that had already gained familiarity with the FPV and was able to incorporate prior learnings, delivering added efficiencies as the industry continues to explore methods to meet growing energy demand with more sustainable operations.

*JF Subtech delivered the work via the now legacy brand James Fisher Marine Services.


Adhering to Premier’s risk based inspection plan, inspection works complied with DNV GL’s guidance for underwater inspection in lieu of dry-docking (UWILD). There were also a number of separate inspections, anode replacements and hull aperture blanking plate installations to carry out, in addition to the UWILD requirements.

Work from the FPV included diving through the platform’s moon pool and covered assets down to water depths up to -25.0m lowest astronomical tide. In total, JFMS successfully completed over 140 operational dives, spending 225 hours underwater.

The project scope involved the installation of replacement anodes (~50kg in water) on the underside of the pontoons, for which JFMS had previously designed and fabricated a bespoke installation/buoyancy frame to aid the diving team during this phase.