Subsea SCR Lifting Frame for Flex Joint Replacement
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Solution Overview
Problem
Current methods for replacing flex joints in deepwater steel catenary pipeline risers require large winches and deck reinforcements, increasing complexity and cost, and lack efficient underwater replacement solutions.
Innovation Solution
An underwater SCR lifting frame system that eliminates the need for large winches and deck reinforcements by allowing direct subsea lifting and welding of new flex joints, utilizing a customized lift frame and underwater dry welding habitat.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If large winches and deck reinforcements are used for flex joint replacement, then lifting capability is improved, but device complexity and cost increase
Solution Approach 1:
The invention extracts the lifting function from the facility's existing winch system and implements it locally at the flex joint location using a dedicated lift frame with integrated lifting beams. This eliminates the need for large facility-mounted winches and their associated deck reinforcements, thereby reducing overall system complexity while maintaining adequate lifting capability.
Solution Approach 2:
Instead of using the facility's existing winch system to lift the flex joint from above water, the invention inverts the approach by using an underwater lift frame with lifting beams that lift the flex joint directly at its location. This reversal of the lifting mechanism eliminates the need for complex facility-mounted equipment and reduces system complexity.
2Force
If large winches and deck reinforcements are used for flex joint replacement, then lifting capability is improved, but cost increases
Solution Approach 1:
The invention extracts the lifting function from expensive facility-mounted winch systems and implements it using a simpler, dedicated lift frame structure. This extraction eliminates the need for costly deck reinforcements and large winches, thereby reducing manufacturing and installation costs while maintaining sufficient lifting capability for flex joint replacement.
Solution Approach 2:
The invention employs a dedicated lift frame system that is specifically designed for the flex joint replacement operation. This specialized, relatively simple structure replaces the need for expensive, heavy-duty facility-mounted winches and deck reinforcements, thereby reducing overall project cost while achieving the required lifting capability.
3Force
If traditional winch systems are used, then lifting function is achieved, but ease of operation is reduced
Solution Approach 1:
The invention segments the lifting function from the complex facility-mounted winch system and implements it as a dedicated, localized lift frame with lifting beams. This segmentation creates a simpler, more focused system that is easier to operate for the specific task of flex joint replacement, eliminating the need to manage complex facility-wide equipment.
Solution Approach 2:
Instead of operating complex facility-mounted winches from above water, the invention inverts the approach by using an underwater lift frame with lifting beams that are directly positioned at the flex joint. This inverted approach simplifies operation by bringing the lifting mechanism closer to the work location and eliminating the need for complex steering and positioning operations.
Data Source
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AI summary
An underwater steel catenary pipeline riser (SCR) lifting frame (1) comprises a lift frame foundation (10) and an SCR lifting frame (20) comprising a lift frame interface (21) adapted to be connected to the lift frame foundation; a foundation interface (50); a lift guide (30) configured to accept the lift frame foundation; and a lift (32) slidably disposed about the lift guide, the lift comprising an SCR pull head interface (31) configured to be connected to an SCR pull head (131). The underwater steel catenary pipeline riser (SCR) lifting frame (1) and systems using it allow for flex joint repair/replacement subsea which do not require large winches, deck re-enforcements, steering winches, and heavy crane lifts required by facility mounted winches above water and also reduces required heavy lifting and overall complexity of flex joint replacement.