Ratcheted E-ring Retention for Wellhead Seal Stability
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Solution Overview
Problem
Metal-to-metal seals in subterranean wells experience leakage due to the energizing ring backing out of the seal pocket under cyclic loads and pressures, requiring high setting loads and specialized tools for assembly, and lacking flexibility in placement.
Innovation Solution
A seal assembly with a ratchet retainer and ratcheted clip that prevents the energizing ring from backing out, allowing for flexible placement and reduced setting load requirements, utilizing a ratcheted retainer and clip with circumferentially extending teeth for secure engagement without the need for presses or special tools.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single bump feature is used to retain the energizing ring, then the assembly structure is simple, but the setting load is high and a press is required for assembly
Solution Approach 1:
The retention mechanism is divided into multiple features: a first bump feature for initial retention and a second bump feature for final retention after the seal ring is set. This segmentation allows the energizing ring to be retained during both the setting operation and normal operation, eliminating the need for high setting loads while maintaining structural simplicity
Solution Approach 2:
The first bump feature is positioned to engage the energizing ring before the setting operation, providing preliminary retention during the seal ring setting process. This preliminary action prevents the energizing ring from moving axially during setting, eliminating the need for high setting loads and specialized assembly tools
2Manufacturing precision
If the energizing ring is forced into the seal ring until the bump feature is passed, then the seal ring can be set, but the energizing ring can back out during operation causing leakage
Solution Approach 1:
The retention mechanism uses two distinct bump features: the first bump feature retains the energizing ring during the setting operation to ensure precise positioning, while the second bump feature retains the energizing ring during normal operation to prevent backout and leakage. This segmentation allows both precise setting and reliable operation
Solution Approach 2:
The second bump feature acts as an intermediary retention mechanism that engages the energizing ring after the seal ring is set. This intermediate feature prevents the energizing ring from backing out during operation, maintaining seal integrity without interfering with the initial setting process
3Manufacturing precision
If a press is required to assemble the energizing ring into the seal ring, then the bump feature can be passed, but the assembly process becomes complex and requires special tools
Solution Approach 1:
The first bump feature is designed to engage the energizing ring before the setting operation, providing preliminary retention that maintains precise positioning during the seal ring setting process. This preliminary action eliminates the need for high setting loads and specialized assembly tools, allowing manual or simple tool assembly
Solution Approach 2:
The bump features are designed to engage and disengage dynamically during the assembly and operation cycles. The first bump feature engages during assembly to provide retention, then the second bump feature engages after setting to provide operational retention. This dynamic engagement allows simple assembly without presses while maintaining manufacturing precision
4Device complexity
If the energizing ring is retained with a single bump feature, then the device is simple, but there is no flexibility in placement of the energizing ring relative to the seal ring
Solution Approach 1:
The retention mechanism is segmented into two bump features at different axial positions: the first bump feature for retention during setting and the second bump feature for retention during operation. This segmentation provides flexibility in placing the energizing ring at the appropriate position relative to the seal ring while maintaining device simplicity
Solution Approach 2:
The first bump feature provides preliminary retention at an initial position, allowing the energizing ring to be placed correctly during assembly. The second bump feature then provides operational retention at the final position. This two-stage preliminary and operational retention provides placement flexibility without increasing device complexity
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 effectively maintains the seal under operational conditions, reducing leakage and allowing for easier assembly and adjustment of the seal assembly with minimal increase in setting load, providing flexibility in the placement of the energizing ring relative to the seal ring.
Implementation Method 1
A ratchet clip is located within the recess. The ratchet clip has a clip profile on a radially outward surface of the ratchet clip. The recess and the ratchet clip extend less than a full circumferential distance around the outer diameter of the annular energizing ring or the radially inner diameter of the seal ring. A retainer profile on the ratcheted retainer selectively engages the clip profile of the ratchet clip.
Data Source
AI summary
A wellhead assembly includes an outer tubular wellhead member and an inner tubular wellhead member with a seal pocket between them. A seal ring is located in the seal pocket. An annular energizing ring urges the seal ring into sealing engagement with the outer tubular wellhead member and the inner tubular wellhead member. A recess is located on an outer diameter of the annular energizing ring or a radially inner diameter of the seal ring, and a ratcheted retainer is on the other. A ratchet clip with a clip profile is located within the recess. The recess and the ratchet clip extend less than a full circumferential distance around the outer diameter of the annular energizing ring or the radially inner diameter of the seal ring. A retainer profile on the ratcheted retainer selectively engages with the clip profile of the ratchet clip.