Single Annular Piston Wellhead Connector Design
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Solution Overview
Problem
Existing subsea wellhead connectors are large, heavy, and expensive due to their complex design featuring multiple pistons and a large cam ring, which complicates manufacturing and operation.
Innovation Solution
A wellhead connector design utilizing a single annular piston and a reduced-proportion cam ring, with connecting rods and a secondary piston for enhanced efficiency and reliability, allowing for a lighter and less expensive construction while maintaining locking and unlocking functionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple pistons and a large cam ring are used, then the connector achieves reliable locking and unlocking functionality, but the connector becomes large, heavy, and expensive to manufacture
Solution Approach 1:
Multiple pistons are merged into a single annular piston that performs the function of all pistons simultaneously. The annular piston has a continuous circumferential surface that interacts with the cam ring around the entire circumference, eliminating the need for multiple separate pistons while maintaining reliable locking and unlocking functionality.
Solution Approach 2:
The single annular piston serves multiple functions: it moves the cam ring axially between locked and unlocked positions, provides uniform force distribution around the circumference, and eliminates the need for multiple pistons. This multi-functional design reduces weight while maintaining reliability.
2Reliability
If multiple pistons and a large cam ring are used, then the connector achieves reliable locking and unlocking functionality, but the connector becomes large and expensive to manufacture
Solution Approach 1:
Multiple pistons are merged into a single annular piston that performs the function of all pistons simultaneously. The annular piston has a continuous circumferential surface that interacts with the cam ring around the entire circumference, eliminating the need for multiple separate pistons while maintaining reliable locking and unlocking functionality.
Solution Approach 2:
The complex multi-piston mechanism is extracted and replaced with a simpler single annular piston design. This extraction of complexity reduces the number of parts, simplifies manufacturing, and lowers cost while preserving the essential locking and unlocking functions through the annular piston's continuous circumferential action.
3Strength
If a large cam ring is used, then the connector achieves sufficient contact area and load distribution, but the connector becomes large and heavy
Solution Approach 1:
Instead of uniformly thickening the cam ring throughout, the design uses localized load distribution features. The cam ring profile is optimized with specific geometric features at critical locations to ensure adequate load distribution and contact area only where needed, reducing overall weight while maintaining strength.
Solution Approach 2:
The cam ring dimensions and profile parameters are optimized to achieve sufficient contact area and load distribution with reduced mass. The annular piston's continuous circumferential surface provides uniform force distribution, allowing for a lighter cam ring design that still achieves adequate load distribution through optimized geometric parameters.
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 design results in a smaller, lighter, and more efficient wellhead connector that is less expensive to manufacture, with improved mechanical efficiency and reliability, including a secondary piston for fail-safe unlocking.
Implementation Method 1
A wellhead connector utilizes a singular annular piston to lock the connector onto the wellhead
Implementation Method 2
The cam ring is of a reduced proportion relative to prior art. As such, the cam ring outer side is dimensioned to contact the inner side of the connector housing under load
Implementation Method 3
At preload, a profile on the lower portion of the connector body engages a stepped profile on the outer diameter of the wellhead thereby creating a secondary load path for reacting to the applied bending moment
Data Source
AI summary
A wellhead connector for connecting a riser or production tree to a wellhead of a subsea well utilizes a singular annular piston to lock the connector onto the wellhead. The wellhead connector includes a housing that contains dogs for engagement with the exterior of the wellhead housing. A cam ring is also included, which has an inner side for engaging the dogs and moving them inward into a locked position with the wellhead housing. The cam ring is of a reduced proportion relative to prior art. As such, the cam ring outer side is dimensioned to contact the inner side of the connector housing under load. Connecting rods connect the piston to the cam rings. As the piston moves downward, the cam ring also moves downward, forcing the dogs inward into a locked position. As the piston moves upward, the cam ring also moves upward, thereby unlocking the connector. A secondary annular piston is also provided to guarantee unlocking.At preload, a profile on the lower portion of the connector body engages a stepped profile on the outer diameter of the wellhead thereby creating a secondary load path for reacting to the applied bending moment.