Energizing Ring Nose Profile for Wellhead Seal Sequence Control
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Solution Overview
Problem
Existing wellhead seal systems face issues with seal leakage due to premature deformation of metal-to-metal seals before the emergency seal is adequately compressed, which can compromise pressure integrity.
Innovation Solution
A seal assembly featuring a metal energizing ring with a tapered nose and compound angle configuration that delays the deformation of the metal seal, allowing for controlled compression of an elastomeric emergency seal to ensure proper sealing engagement with wellhead members, and a retainer ring for secure locking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the metal seal ring is deformed against the inner and outer wellhead members before the emergency seal is compressed sufficiently, then the metal-to-metal seal engagement is achieved, but the emergency seal cannot perform its function and pressure integrity diminishes
Solution Approach 1:
The tapered nose geometry is designed to automatically compress the emergency seal before the metal seal ring walls are deformed into sealing engagement. The gradual taper allows the emergency seal to bulge outward and contact the wellhead members first, establishing a preliminary seal that maintains pressure integrity even if the metal seal fails.
Solution Approach 2:
The compound angle configuration of the tapered nose changes the force distribution parameters during installation. By optimizing the taper angles, the design controls the sequence of deformation events, ensuring that the emergency seal receives sufficient compression force before the metal seal ring walls engage with the wellhead members.
2Reliability
If a solid wedge-shaped energizing ring is used to deform the metal seal ring, then the metal-to-metal seal is engaged, but the emergency seal may not be adequately compressed before seal ring deformation
Solution Approach 1:
The energizing ring features a compound angle tapered nose with specific geometric parameters optimized for sequential seal engagement. The local geometry of the tapered nose creates different force application zones: the gradual taper compresses the emergency seal first, while the subsequent sharper angles drive the metal seal ring walls into engagement with the wellhead members.
3Ease of operation
If the radial gap between the outer wall of the seal and the inner wall of the mating housing is large enough to allow installation, then plastic deformation of the seal body is required, but this may cause premature seal deformation
Solution Approach 1:
The compound angle tapered nose geometry is specifically designed to accommodate the radial gap required for field installation. The gradual taper allows the seal body to deform plastically in a controlled manner as the energizing ring is forced into the slot, ensuring that deformation occurs in the correct sequence without compromising installation feasibility.
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
Enhances emergency sealing capabilities by ensuring the emergency seal is sufficiently compressed before the metal-to-metal seal engages, maintaining pressure integrity and preventing seal failure.
Implementation Method 1
The deformation of the inner and outer walls exceeds the yield strength of the material of the seal ring 4, making the deformation permanent.
Implementation Method 2
compress the elastomeric seal to cause it to bulge outwards
Data Source
AI summary
A wellhead seal assembly that forms a metal-to-metal seal between inner and outer wellhead members. A metal seal ring has inner and outer walls separated by a slot. An elastomeric seal is located below the seal ring and has a bottom portion that contacts an upward facing shoulder of a hanger. An energizing ring with a tapered nose is moved into the slot. The tapered nose has a compound angle that determines how much the nose travels into the slot when a force is applied to the energizing ring. Once the elastomeric seal is compressed to a desired level, the load on the energizing ring has increased to the point that the tapered nose of the energizing ring will further enters the slot and force the outer and inner walls of the metal seal into sealing engagement with the inner and outer wellhead members.