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Different methods of replacing flare tips offshore

‍Mechanical Flare Tip Handling

Mechanical handling involves the use of lifting structures installed at the top of the flare tower, which can be either permanent or temporary. These structures are erected manually, supported by general rigging equipment. Before use, the system is typically load tested to ensure safety and reliability. A winch positioned at deck level is reeved through the lifting system at the top of the stack, allowing controlled lifting and lowering of the flare tip. The operation usually requires a crew of 5 to 8 people, depending on the complexity of the flare tip and any additional activities involved. The shutdown period for this method typically ranges from 4 to 10 days.

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Replacement Using a Crane Vessel

This method involves deploying a crane vessel with sufficient lifting height to reach the flare tip, often more than 100 meters above sea level. While the weight of the flare tip is rarely a limiting factor, the lifting height is critical. The actual replacement can be completed in one shutdown day, but it still requires a crew of 3 to 5 people to access the flare tip platform and perform the installation. Despite its speed, this method involves higher costs and more complex logistics.

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Replacement Using a Helicopter

Helicopter-assisted replacement requires special preparation on the platform, including the installation of a catch-and-release system. This system enables quick fixation and disconnection of the flare tip, minimizing the time the helicopter's long line is connected to a fixed structure, a critical safety consideration. Helicopters used for this purpose can typically lift flare tips weighing up to 3,000 to 4,000 kg. The operation involves 3 people on the platform, and a shutdown period of approximately 2 days is sufficient for preparation and execution.

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Cost Effectiveness of Each Method

- Mechanical Handling: Total costs typically range between EUR 200,000 and EUR 500,000, including engineering, project preparation, equipment rental, and crew. This method offers a balanced cost profile for most offshore projects.

- Crane Vessel: The cost is driven by the day rate and mobilization/demobilization fees of the crane vessel, which can total up to EUR 1.5 million. Additional costs include engineering, crew, and platform preparation.

- Helicopter: Costs vary significantly by region. In the North Sea, a helicopter operation can be mobilized for around EUR 500,000, while in other parts of the world, costs may rise to EUR 1 - 2 million per deployment.

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Project Flexibility Considerations

Mechanical Handling requires early planning and should be awarded 9 to 12 months before the scheduled shutdown. Once the lifting system is available, day rates are relatively low, offering flexibility in execution. Crane Vessels and Helicopters must be booked well in advance due to limited availability. There is always a risk that the asset operator may cancel the contract last minute if a more profitable job arises, this risk is especially high with crane vessels.

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Conclusion: Choosing the Right Method for Your Shutdown

If your planned shutdown allows for 4 to 10 days, the mechanical handling method is often the most practical and cost-effective solution. It offers low risk to budget and schedule and can be managed with a moderate crew size. However, if your shutdown window is limited to just one day, it may be worth investing in a crane vessel or helicopter operation to meet the timeline. In all cases, it's essential to consult with the experts at Conbit to determine the best method for your specific project conditions.