Expandable Segmented Support Ring for Downhole Elastomer Seal Extrusion
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Solution Overview
Problem
Elevated pressures cause elastomer seals in downhole packers to be pushed out of position, leading to longitudinal extrusion and failure of the annular seal, potentially resulting in a blowout.
Innovation Solution
An expandable support ring system comprising multiple segments with a 45-degree back angle, made of steel, which interacts with an expander cone to prevent extrusion by compressing the elastomer seal against the casing wall under internal pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If elastomer seals are used in downhole packers, then sealing capability is improved, but under elevated pressures the seals become pushed out of position and undergo longitudinal extrusion leading to failure
Solution Approach 1:
The support ring is divided into multiple segments (e.g., 20 segments) that can independently deform and expand. Each segment acts as an individual support element, collectively providing comprehensive support to prevent seal extrusion while allowing controlled expansion under pressure.
Solution Approach 2:
The support ring is pre-installed in a compressed state within the packer assembly before deployment. The segments are initially compact to allow easy insertion, then expand in-place to engage with the seal and provide preventive support against extrusion before pressure conditions occur.
2Reliability
If a rigid support structure is used to prevent seal extrusion, then seal stability is improved, but the device complexity and difficulty of deployment increase
Solution Approach 1:
The support ring transitions from a static, rigid structure to a dynamic, expandable system. The segments can change their configuration from a compact state during deployment to an expanded state during operation, adapting to different operational phases and reducing overall system complexity.
Solution Approach 2:
The support ring segments are designed as flexible, thin-walled structures that can deform and expand. This flexibility allows the support structure to be compact during insertion while providing rigid support when expanded, eliminating the need for complex mechanical mechanisms.
3Ease of manufacture
If the support ring is made as a single piece, then manufacturing is simpler, but it cannot expand to provide adequate support under high pressure
Solution Approach 1:
The support ring is divided into multiple segments that can be manufactured separately using standard fabrication processes, then assembled together. This segmentation enables both ease of manufacture (each segment is simple to produce) and expandability (segments can move relative to each other).
Solution Approach 2:
Multiple individually manufactured segments are combined to form the complete support ring assembly. The segments work together as a unified structure when expanded, providing the necessary support while maintaining manufacturing simplicity for each component.
4Strength
If the support ring expands under internal pressure, then support capability is improved, but the force required to expand the seal and support ring increases
Solution Approach 1:
The total expansion force is distributed across multiple segments rather than requiring one large force. Each segment expands independently with a portion of the total force, reducing the peak force requirement while achieving the same overall support capability.
Solution Approach 2:
The support ring segments expand progressively rather than all at once, with each segment providing partial support as it expands. This staged expansion reduces the instantaneous force requirement while achieving full support capability.
Data Source
AI summary
A support ring prevents an elastomer seal from extruding. The support ring is expanded and supports the expanded seal, preventing the elastomer seal failing due to extrusion.