Gap Holding & Weighing
Technical Challenges in Decommissioning and Abandonment
In the decommissioning and abandonment sector, a critical challenge is accurately weighing individual modules before disposal. Removing and recycling topside and substructure equipment are significant cost factors in global platform decommissioning. Consequently, these processes are key targets for reducing both time and costs.
Traditionally, cutting concrete platform legs or module bases involves using wedges, levers, and crane supports to prevent diamond cutting wires from becoming trapped. Time spent freeing stuck or broken wires can significantly impact operational productivity, often requiring additional structural analysis during the engineering phase to avoid such issues.
The weight of offshore platform topsides directly influences the overall economics of a decommissioning project. Historically, determining the weight and centre of gravity of multi-tonne modules before heavy lifting, skidding, or trailering has involved methods such as calculations based on original 2D/3D construction drawings or using large-capacity load cells placed underneath the object.
PowerPad™
Building on the success of ThinJack® technology, PowerPad™ is a millimetric-thin, hydraulically inflatable steel envelope designed to support and maintain gap height during cutting operations.
Key Features:
- Real-Time Monitoring: Custom-designed software displays individual PowerPad inflation pressures, load readings, and total load in real time.
- Adjustable Support: Positioned in the cut gap and connected to a hydraulic pump via a manifold with individual control valves, PowerPads are pressurised with water. They expand to maintain the gap opening and adjust in real time to counteract adverse forces from downward pressure.
Advantages:
- Enhanced Cutting Efficiency: PowerPads prevent objects from collapsing into the cut gap, reducing the risk of damaging the diamond wire and causing delays. This leads to faster and safer operations.
- Accurate Weighing: With specialised software, the patented application can also accurately weigh large structures and determine their centre of gravity when placed underneath them.
- Superior to Solid Shims: Unlike solid passive shims, PowerPads can be inflated to fully fill the gap, equalising forces from above and minimising tension on the cutting wire. Solid shims, while they may slide into the gap, cannot fully pack it or support forces from above, leading to higher tension and potential damage (such as crazing concrete).
Applications:
- Concrete Cutting: PowerPads provide effective support during concrete cutting operations, preventing gaps from closing and ensuring smoother progress.
- Structural Weighing: After cutting, PowerPads support the upper part of the asset, allowing for accurate weight and centre of gravity calculations. This capability enables the use of a wider range of vessels for topside disconnection, potentially reducing costs for various structure sizes.
