Rigid Riser Bottom-to-Surface Connection Using Positive Buoyancy
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing bottom-to-surface connections for offshore oil and gas production are complex, expensive, and require flexible hinges that are difficult to fabricate and prone to fatigue, with issues of mechanical strength and stability due to tension discontinuities and large angular variations.
Innovation Solution
A bottom-to-surface connection installation using a vertical rigid riser with a terminal inertia transition piece and a flexible connection pipe providing positive buoyancy, eliminating the need for flexible hinges and gooseneck devices, and allowing for a single automatic connector between the riser and the sea bottom, with a simplified fabrication and installation process at sea.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If flexible hinges are used to connect the vertical riser to the anchor device, then the riser can accommodate angular variations, but the fabrication becomes difficult and fatigue issues arise
Solution Approach 1:
The patent removes the flexible hinge component entirely from the system. Instead of using a flexible hinge to connect the vertical riser to the anchor device, the invention employs a rigid clamped connection that directly fastens the riser to the anchor device, eliminating the source of fatigue and fabrication difficulties while maintaining angular variation accommodation through the rigid connection's structural design
Solution Approach 2:
The patent inverts the conventional approach by using a rigid connection instead of a flexible one. Rather than allowing flexibility at the connection point to handle angular variations, the rigid clamped connection with proper mechanical fastening achieves both structural integrity and angular accommodation through its design, turning the weakness of rigidity into a strength
2Adaptability or versatility
If flexible hinges and gooseneck devices are used, then connection flexibility is achieved, but mechanical strength and stability are reduced due to tension discontinuities
Solution Approach 1:
The patent removes flexible hinges and gooseneck devices from the connection system. The rigid clamped connection directly fastens the vertical riser to the anchor device without intermediate flexible components, eliminating tension discontinuities and maintaining continuous mechanical strength throughout the connection while still achieving the necessary flexibility through the rigid connection's structural design
Solution Approach 2:
The patent employs a composite connection structure combining the rigid riser, clamped connection mechanism, and anchor device into an integrated assembly. This composite structure achieves both flexibility and strength by designing the rigid components to work together as a unified system rather than relying on separate flexible and rigid elements
3Reliability
If complex connection devices are used, then connection capability is enhanced, but device complexity and installation cost increase
Solution Approach 1:
The patent merges the functions of flexible hinges, gooseneck devices, and clamped connections into a single integrated rigid clamped connection. This unified connection mechanism directly fastens the vertical riser to the anchor device, combining multiple functions into one simple device that reduces complexity while maintaining or enhancing connection capability and reliability
Solution Approach 2:
The rigid clamped connection serves multiple functions simultaneously: it provides structural support, accommodates angular variations, ensures mechanical strength, and simplifies installation. This multi-functional design eliminates the need for separate specialized components, reducing overall device complexity while enhancing connection capability
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 reduces angular variations, enhances mechanical strength, and simplifies installation and maintenance, while reducing costs and complexity by using a rigid clamped connection and positive buoyancy to maintain the riser in a stable vertical position.
Implementation Method 1
the positive buoyancies of said terminal portion of the flexible pipe and of said top portion of the vertical riser enable said riser to be tensioned in a substantially vertical position and enable alignment or continuity of curvature to be achieved between the end of said terminal portion of the flexible pipe and the top portion of said vertical riser where they are connected together
Data Source
AI summary
A bottom-to-surface connection installation of at least two undersea pipes (10a, 10b) resting on the sea bottom, the installation comprising:1) a first hybrid tower comprising:a) a vertical riser (1a) anchored (3a) to a first base and connected to a said undersea pipe (10a) resting on the sea bottom and having its top end connected to a first sub-surface float (2a); andb) a first connection pipe (4a) preferably a flexible pipe, providing the connection between a floating support (11) and the top end of said riser; and2) at least one second rigid pipe (1b) rising from the sea bottom on which it rests (10b) or from a second undersea pipe resting on the sea bottom to which its bottom end is connected, said bottom end not being anchored at said first base, up to the sub-surface where its top end is connected to a second float (2b) situated substantially at the same depth as said first float (2a) and fastened to said first float at least respectively a flexible second connection pipe (2b) providing its connection with the same said floating support (11).