Safe and cost-effective single-lift removal technology for decommissioned fixed offshore steel platform substructures (“jackets”)

The Patented DeltaLifter Principle

The DeltaLifter is a single-lift tool specifically developed for safe & low-cost removal and transportation to shore of large decommissioned offshore platform jackets, without use of heavy-lift crane vessels or flat-top barges. The DeltaLifter enters the decommissioning process after the platform deck has been lifted off and piles and other subsea connections have been cut. The sole purpose of the DeltaLifter is the safe removal of the jacket, which normally is the largest and heaviest part of an offshore fixed steel platform.

DeltaLifter moving into position

The DeltaLifter being manoeuvred into position (by 4 tugs), no anchors are used. The DeltaLifter is unmanned and power and signals are transmitted through cables from containerised power and control units on the deck of an adjacent supply boat. All systems are fail safe and have full redundancy.

DeltaLifter alongside the jacket

The DeltaLifter is ballasted down and carefully positioned alongside one side of the jacket. In a shallow-water mode the DeltaLifter may rest and rotate on the seabed if appropriate; in a deep water mode it will connect higher up. Pre-positioned cradles on the DeltaLifter deck will serve as guide structures for mating with the jacket.

DeltaLifter connected to top of the jacket

The DeltaLifter being connected to the top of the jacket. No underwater work is required. All necessary structures for connecting the jacket to the DeltaLifter will have been installed prior to arrival of the DeltaLifter. Most (or all) seabed connections will have been cut off prior to the arrival of the DeltaLifter using proven methods

DeltaLifter - tilt-up operation

Tilt-up operation is achieved by controllled de-ballasting of the DeltaLifter

DeltaLifter in tow-to-shore condition

The DeltaLifter in its tow-to-shore condition. The tow-to-shore is carried out in a semi-submerged condition. This enhances the superior motion characteristics of the DeltaLifter.

DeltaLifter skidded onto recycling yard

The DeltaLifter is ballasted on an even keel and the jacket is skidded onto a recycle yard using conventional hydraulic skidding technology. The maximum draft of 8 meters allows access to a number of alternative recycle sites.

Animation Video of the DeltaLifter Removal Cycle