Wave-Configuration Subsea Riser Installation With Adjustable Clump Weight
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Solution Overview
Problem
The conventional installation method for wave-configuration subsea risers requires an additional support vessel to handle clump weights, leading to increased operational costs, capital asset tie-up, and safety risks, with complex and time-consuming procedures that limit installation to specific weather conditions and increase the risk of disruption due to bad weather.
Innovation Solution
A method involving a clump weight device in a double catenary shape, connected to a winch or crane onboard the installation vessel, allowing continuous control and adjustment of the weight load applied to the riser, eliminating the need for a support vessel and enabling installation in higher sea states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional installation method using a support vessel to handle clump weights is used, then the riser installation can be completed with traditional procedures, but operational costs increase, capital assets are tied up, and safety risks increase
Solution Approach 1:
The patent combines the functions of the installation vessel and support vessel into a single system. The installation vessel's winch handles both riser deployment and clump weight installation, eliminating the need for a separate support vessel and reducing overall system complexity while maintaining installation reliability
Solution Approach 2:
The installation vessel's winch is used for multiple purposes: deploying the riser, installing clump weights, and recovering clump weights. This multi-functional approach eliminates the need for specialized equipment and reduces capital asset requirements
2Ease of manufacture
If a conventional installation method with support vessel is used, then traditional installation procedures can be followed, but installation time increases and operational costs increase
Solution Approach 1:
The patent enables continuous installation operations without pausing for clump weight installation or recovery. The winch can seamlessly transition between deploying riser sections and installing/clump weights, eliminating downtime and improving installation productivity while maintaining procedural simplicity
Solution Approach 2:
Clump weights are prepared and positioned in advance on the installation vessel, allowing for rapid installation when needed. This preliminary preparation eliminates time-consuming on-site assembly operations and accelerates the overall installation process
3Reliability
If conventional installation procedures are used, then traditional safety protocols can be followed, but the risk of disruption due to bad weather increases
Solution Approach 1:
The installation vessel is equipped to perform all necessary operations (riser deployment, clump weight installation and recovery) with its existing winch system, eliminating the need for a second support vessel. This reduces the number of vessels operating in rough seas, improving safety while maintaining the ability to operate in higher sea states
4Shape
If clump weights are installed and recovered during installation, then the desired hogbend shape can be achieved, but installation must be paused and operational efficiency decreases
Solution Approach 1:
The patent enables continuous installation operations where the winch seamlessly transitions between deploying riser sections and installing or recovering clump weights. This eliminates pauses in the installation process while maintaining the ability to achieve the desired hogbend shape through controlled clump weight positioning
Solution Approach 2:
The patent employs dynamic control of clump weights during installation, allowing them to be installed and recovered in real-time as the riser is deployed. This dynamic approach enables continuous installation while maintaining proper riser configuration, eliminating the need to pause operations
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 reduces installation time and costs, minimizes compressive loads and dynamic amplification factor, and allows for continuous operation without pausing for clump weight installation or recovery, enhancing safety and flexibility in sea state limits.
Implementation Method 1
suspending an elongate clump weight in a catenary shape comprising first and second limbs extending upwardly from a conjoining bottom portion
Implementation Method 2
controlling a weight load applied by the clump weight to the riser by adjusting relative lengths of the first and second limbs of the clump weight
Data Source
AI summary
A method of installing a wave-configuration subsea riser of unbonded flexible pipe comprises lowering the riser progressively into the sea from an installation vessel while suspending an elongate clump weight in a catenary shape that comprises first and 5 second limbs extending upwardly from a conjoining bottom portion. An upper end of the first limb, at a distal end of the clump weight, is attached to the riser and an upper end of the second limb, at a proximal end of the clump weight, is suspended from a winch or crane of the vessel. While lowering the riser from the vessel, the weight load applied to the riser by the clump weight is controlled by adjusting the relative lengths of the first 0 and second limbs of the clump weight.