Subsea Vessel Riser Storage and Handling System
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Solution Overview
Problem
The existing methods for assembling and handling subsea riser strings are time-consuming and inefficient, particularly due to the need for repetitive connection testing and the heavy weight of riser sections, which complicates the deployment and retrieval process.
Innovation Solution
The implementation of a vessel with dedicated storage racks for both first and second length riser sections and pre-assembled riser stands, along with a dual elevator system and overhead cranes, allows for efficient storage, handling, and assembly of riser sections, reducing the time required for deployment and retrieval by enabling the use of pre-assembled stands and optimizing buoyancy module distribution for easier handling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If riser sections are stored and handled using conventional methods with single-length storage racks and manual assembly processes, then the vessel can store and deploy riser sections, but the assembly process becomes time-consuming and inefficient due to repetitive connection testing and heavy weight handling
Solution Approach 1:
The invention segments the storage system into two distinct types of storage racks: first length storage racks for longer riser sections (e.g., 150 ft) and second length storage racks for shorter riser sections (e.g., 75 ft). This segmentation allows for optimized handling and assembly processes for each length type, reducing the time required for connection testing and assembly by enabling more efficient retrieval and positioning of riser sections during string assembly operations.
2Productivity
If pre-assembled riser stands are used to reduce assembly time, then the deployment efficiency improves, but the storage and handling complexity increases due to the need for specialized storage racks and handling equipment
Solution Approach 1:
The invention implements preliminary action by providing dedicated first length storage racks configured to store pre-assembled riser stands (multiple riser sections already connected into stands). This allows riser stands to be prepared in advance and stored in an organized manner, enabling rapid deployment when needed. The specialized storage racks simplify the handling of pre-assembled units compared to managing individual sections, thus improving deployment efficiency without proportionally increasing complexity.
3Adaptability or versatility
If the vessel stores both first length (100+ ft) and second length (50-90 ft) riser sections, then the versatility of the vessel improves, but the storage space requirements and handling system complexity increase
Solution Approach 1:
The invention achieves universality by designing a dual storage rack system where first length storage racks and second length storage racks coexist in the same riser storage hold. Both types of racks follow similar structural principles (horizontal stacking, overhead crane accessibility), allowing the vessel to handle different riser section lengths using a unified handling approach. This multi-functional storage system enables the vessel to adapt to various operational requirements while maintaining efficient use of storage space through standardized rack designs.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach significantly reduces the time needed for assembling and disassembling the riser string, minimizes the number of pressure tests required, and enhances safety by allowing for quicker inspection and maintenance of subsea equipment, thereby improving the efficiency of subsea drilling operations.
Implementation Method 1
a first overhead travelling beam crane arranged within the riser storage hold, said first crane being adapted to lift and lower a single riser section or a single riser stand
Implementation Method 2
said first crane being adapted to lift and lower a single riser section or a single riser stand at least allowing for removal of a single riser section or a single riser stand riser stand from a storage rack
Implementation Method 3
provided with a transfer elevator that is adapted to raise and lower a single riser section or a single riser stand in horizontal orientation
Implementation Method 4
optimizing buoyancy module distribution for easier handling
Data Source
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AI summary
A vessel adapted to perform subsea wellbore related operations involving a riser string between the subsea wellbore and the vessel, e.g. drilling and/or wellbore intervention, said vessel comprising a hull having a deck. The vessel comprises a riser storage hold present within said hull below said deck, which riser storage hold comprises storage racks adapted to store therein parallel stacks of multiple riser sections and/or pre-assembled riser stands in horizontal orientation. The vessel has an elongated riser transfer opening between said deck and said roof, said riser transfer opening extending in a direction parallel to said storage racks, said riser transfer opening having a length and a width so as to allow for transfer of a single riser section or a single riser stand in horizontal orientation via said riser transfer opening out of and into the riser storage hold.