Protecting Offshore Asset Integrity with a Bespoke Subsea Caisson Clamp

THREE60 Energy was engaged to develop a safety-critical solution that would mechanically secure the caisson and retain the load in the event of failure.

Following operational issues on an offshore asset, an operator identified concerns around the structural integrity of a subsea caisson. With no secondary support structure in place, a failure could result in the caisson falling to the seabed and causing significant damage to surrounding infrastructure.

THREE60 Energy was engaged to develop a safety-critical solution that would mechanically secure the caisson and retain the load in the event of failure.

Challenge

The existing caisson was already installed subsea within a guide structure, significantly restricting access and making installation of additional support complex.

Any solution needed to withstand the full caisson load while remaining compact enough for diver installation, with minimal subsea assembly. Installation also required holes to be drilled through both sides of the caisson with sufficient accuracy to ensure the securing pin could pass completely through the structure.

Solution

THREE60 engineered a bespoke one-piece hinged clamp, incorporating all bolts and fixings within the design to minimise loose components during subsea installation. Detailed engineering analysis was undertaken to confirm the clamp could withstand the full caisson load.

The proposed installation was then replicated in THREE60’s submerged test facility in Aberdeen, allowing different drilling methods to be trialled and the design refined before mobilisation. Bespoke mounting plates were developed to improve drilling accuracy, repeatability and ease of use for the divers.

Following successful trials and training, THREE60 also project managed the provision of the installation contractor’s back-deck equipment, including hydraulic power units, downlines, reelers, subsea drills and associated rigging and handling equipment.

Result

The bespoke clamp and installation methodology were successfully developed, tested and deployed, providing the operator with a mechanical safeguard against potential caisson failure.

The project was delivered on time and within budget, combining engineering analysis, bespoke design, full-scale testing, diver installation planning and equipment provision into a single integrated solution.

Related Content

01

Unlocking New Opportunities at Ringhorne Through Integrated Subsurface Screening

As hydrocarbon fields mature, maximizing recovery and identifying new opportunities become increasingly important to sustain production and extend field life. The Ringhorne Field, located in the North Sea on the Norwegian Continental Shelf, has been producing since 2003 and remains an important core asset within the Greater Balder Area for Vår Energi. 

Three60 Web Graphics 0 2 16
02

Well Management: Onshore Exploration Wells

THREE60 Energy delivered full well management for two remote onshore exploration wells, integrating well engineering, regulatory submissions, procurement and operations to safely deliver both wells within demanding permit schedules and agreed budgets.

Three60 Web Graphics 0 2 16
03

Scan2Fab on Bumi Armada's Kraken FPSO

Working with Bumi Armada, THREE60 Energy deployed its Scan2Fab process to provide an efficient, end-to-end solution from offshore survey through to fabrication. Combining high-accuracy 3D laser scanning with engineering and fabrication expertise, the approach captures accurate as-built data, reduces the need for repeat site visits and enables components to be designed and manufactured with confidence. The result is a streamlined workflow that helps reduce interfaces, minimise offshore activity and support safe, efficient project delivery.

Three60 Web Graphics 0 2 16