Riser Assembly Buoyancy Control Deepwater Installation
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Solution Overview
Problem
Current riser assembly configurations in the oil and gas industry face challenges in deep and ultra-deep water environments due to extreme environmental conditions, such as high pressures, currents, and wave motions, leading to pipe damage and increased installation costs, particularly with mid-water arch structures.
Innovation Solution
A riser assembly with buoyancy compensating elements and tethering elements, such as metal chains or damped biasing systems, is used to control the shape and movement of the riser, preventing overbending and collision with adjacent structures, while maintaining a predetermined configuration and reducing installation costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If mid-water arch structures are used to support the riser, then the riser's position and shape are well-controlled, but the installation cost and device complexity increase significantly
Solution Approach 1:
The riser is divided into multiple sections with discrete buoyancy modules attached at predetermined locations along its length. Each buoyancy module independently supports a specific section, allowing modular installation and adjustment without requiring complex mid-water arch structures.
Solution Approach 2:
Buoyancy modules are attached to counteract the weight of the riser at specific locations, providing upward lift to balance gravitational forces. This distributed buoyancy approach replaces the need for complex mechanical support structures while maintaining riser position control.
2Ease of manufacture
If discrete buoyancy modules are attached to the riser, then installation cost is reduced, but the riser's shape control and constraint capability decreases
Solution Approach 1:
Different sections of the riser are provided with different buoyancy characteristics through strategically placed modules. The buoyancy distribution is optimized for each local section to achieve overall shape control while maintaining installation simplicity and cost-effectiveness.
Solution Approach 2:
The riser system allows dynamic adjustment of buoyancy module positions and configurations to adapt to varying operational conditions. This dynamic capability enables shape control without requiring fixed, complex mechanical constraints.
3Ease of operation
If the riser is allowed to move freely in water, then installation is simpler, but the risk of collision with adjacent structures and pipe damage increases
Solution Approach 1:
Buoyancy modules are pre-positioned at predetermined locations along the riser before deployment. This preliminary configuration establishes the desired riser shape and position in advance, preventing collision with adjacent structures during operation while maintaining installation simplicity.
Solution Approach 2:
The buoyancy modules act as intermediary elements between the riser and the surrounding water environment, providing controlled buoyant forces that guide the riser's position and prevent unwanted movements that could lead to collisions.
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
The solution effectively controls the riser's shape and movement, reducing the risk of damage and installation costs, providing a cost-effective alternative to traditional mid-water arch systems by maintaining the riser's configuration within predetermined limits and preventing collisions with adjacent structures.
Implementation Method 1
at least one buoyancy compensating element attached to the riser for providing positive, negative or neutral buoyancy to the riser
Implementation Method 2
at least one damped biasing element connected between the riser and an adjacent underwater structure to control movement of the riser about a neutral position
Data Source
Figure 1a~1b
Figure 2
Figure 3
AI summary
A riser assembly and method of supporting a riser assembly are disclosed. The riser assembly includes a riser;at least one buoyancy compensating element attached to the riser; and at least one damped biasing element for controlling movement of the riser about a neutral position with respect to an adjacent underwater structure. The biasing element is directly or indirectly connected to the riser and is directly or indirectly connectable to the adjacent underwater structure.