Telescopic Fairings for Drilling Risers
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Solution Overview
Problem
The installation and retrieval of drag-reducing fairings on deepwater drilling risers are cumbersome and costly due to their short length, requiring frequent stops and modifications to the buoyancy material, and they do not effectively address side load and vortex-induced vibrations across the entire riser length.
Innovation Solution
A fairing system that remains constant at the same depth as the riser is pulled, with independently supported sections that can be installed and removed without stopping the drilling process, using rotatable connections and rollers for low-friction movement and rotation around the riser, allowing for continuous operation and reduced side drag and vibrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If fairings are made manageable in short sections (7 feet long), then each section can be easily handled and installed, but a multitude of sections is required and installation time increases significantly
Solution Approach 1:
The fairing system is divided into multiple 7-foot sections that can be independently handled and installed. Each section is a manageable unit that can be attached to the riser separately, making the overall system easier to handle despite the need for multiple sections.
Solution Approach 2:
The fairing sections are pre-assembled with connection mechanisms ready for rapid attachment. The connection system is prepared in advance with quick-connect features that allow sections to be attached without complex assembly procedures during installation.
2Reliability
If fairings are attached every 7 feet with load bearing connections, then the fairings can support themselves and pivot properly, but the number of connections required increases and modifies the buoyancy material
Solution Approach 1:
The connection system serves multiple functions: it provides load bearing support, allows pivoting motion, and connects adjacent fairing sections. This multi-functional connection reduces the need for separate components at each junction point.
Solution Approach 2:
The connection mechanism combines the attachment to the riser and the connection between sections into an integrated system. The buoyancy material modifications are consolidated at standardized locations to accommodate multiple connection functions.
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 solution significantly reduces the time and cost associated with installing and retrieving fairings, enabling continuous operation and minimizing side loads and vibrations across the entire riser length, thereby enhancing operational efficiency and safety.
Implementation Method 1
The flow around the round riser and the wing shaped trailing portion will reduce the drag on the riser by as much as 50 percent
Implementation Method 2
The smooth transition from the riser pipe diameter to a fairing profile will naturally tend to reduce the potentially destructive vortex induced vibrations
Implementation Method 3
Buoyancy material is added to these pipes to offset a majority of their weight and limit the top tension required for the system
Data Source
AI summary
The method of installing telescopic fairings system on a vertical pipe such as an oil or gas drilling riser to reduce the flow drag associated the vertical pipe in the currents in an ocean, including providing a rotatable interconnection between fairing sections and supporting the interconnected fairing sections independently from the vertical pipe such that the vertical pipe can be partially removed from the ocean without removing the fairings.