Energizing Ring Retaining Feature for Wellbore Seal
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Solution Overview
Problem
Current annular sealing assemblies in wellheads experience loss of sealing effectiveness and lockdown capabilities due to upward movement of the energizing ring, caused by high pressure and temperature, which results in relative axial movement between the energizing ring and the retainer nut, compromising the seal.
Innovation Solution
Incorporation of mating protrusions on the outer diameter of the energizing ring that engage with mating grooves on the inner diameter of the retainer nut, preventing relative axial movement and maintaining the energizing ring in a fully set position within the annular seal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the energizing ring is made with tapered surfaces to force the legs apart for sealing engagement, then the sealing capability is improved, but the energizing ring can move axially upward under high pressure, compromising the seal
Solution Approach 1:
The energizing ring is segmented with axial slots that allow it to expand radially while maintaining axial positioning. This segmentation enables the ring to force the legs apart for sealing engagement while preventing upward axial movement under high pressure conditions.
Solution Approach 2:
The solution transitions from relying solely on the tapered surface geometry for both sealing and positioning to adding a dimensional constraint through axial slots and engagement features with the retainer nut. This adds axial dimension control while maintaining the radial expansion function.
2Reliability
If the energizing ring is pressed into the annular clearance to force the legs apart, then the sealing engagement is improved, but the upward movement of the energizing ring weakens the lockdown capability
Solution Approach 1:
The energizing ring incorporates axial slots that segment its structure, allowing radial expansion for sealing engagement while preventing upward movement. This maintains the lockdown capability by ensuring the ring remains properly positioned against the retainer nut under high pressure conditions.
Solution Approach 2:
The retainer nut acts as an intermediary component that provides axial positioning for the energizing ring. The engagement features between the ring and retainer nut mediate the interaction, preventing upward movement while allowing the energizing ring to function properly in forcing the legs apart for sealing.
3Reliability
If the energizing ring has a wedge shape to push the legs into sealing engagement, then the sealing effectiveness is improved, but relative axial movement between the energizing ring and retainer nut occurs under high temperature and pressure
Solution Approach 1:
The wedge-shaped energizing ring is provided with axial slots that segment its structure. This allows the ring to maintain its wedge shape for effective sealing engagement while preventing relative axial movement between the ring and retainer nut under high temperature and pressure conditions.
Solution Approach 2:
The solution modifies the physical parameters of the energizing ring by adding axial slots and engagement features. These parameter changes enable the ring to maintain its positioning stability under varying temperature and pressure conditions while preserving its wedge shape functionality for sealing effectiveness.
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 enhances the sealing capability and lockdown capacity of the annular seal, maintaining integrity even under high pressure and temperature conditions by preventing axial movement between the energizing ring and the annular seal, thereby increasing the fatigue life and effectiveness of the sealing assembly.
Implementation Method 1
Mating protrusions on an outer diameter of the energizing ring engage and mate with mating grooves on an inner diameter of the retainer nut, which is secured to the outer leg of the annular seal. The engagement of the mating protrusions with the mating grooves can prevent relative axial movement between the energizing ring and the annular seal during operating conditions.
Implementation Method 2
The energizing ring is generally cylindrical in shape with surfaces that slidingly engage the inner and outer legs of the annular seal to push the inner and outer legs into sealing engagement with the inner and outer wellhead members.
Data Source
AI summary
A wellhead assembly includes an outer wellhead member having a bore and an inner wellhead member located in the bore, defining an annular pocket between the outer and inner wellhead members. A sealing assembly is located within the annular pocket, the sealing assembly having an annular seal and an energizing ring. The energizing ring engages inner and outer legs of the annular seal to push the inner and outer legs into sealing engagement with the inner and outer wellhead members. A retainer nut is threadingly attached to the free end of the outer leg of the sealing assembly. Mating grooves are located on one of an inner diameter of the retainer nut and an outer diameter of the energizing ring and mating protrusions located on the other. The mating protrusions mate with the mating grooves to prevent relative axial movement between the energizing ring and the annular seal.