Segmented Anti-Extrusion Limiter for Retrievable Packers
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Solution Overview
Problem
Retrievable packers in cased well bores face issues with pre-set and extrusion of elastomeric packer elements due to resistance from corkscrew-shaped well bores and hydraulic pressures, leading to potential damage and loss of fluid seal.
Innovation Solution
A pre-set inhibiting extrusion limiter comprising a stepped cone frustum supporting segmented anti-extrusion ring segments with compression springs and an elastomeric ring, along with a push ring to maintain the packer in a non-expanded condition and prevent extrusion, ensuring even gaps and backup sealing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional extrusion limiter is used to prevent packer element extrusion under hydraulic pressure, then extrusion is controlled, but the limiter may snag obstructions in the well bore causing packer element pre-set
Solution Approach 1:
The anti-extrusion ring is divided into multiple segments that can flex and navigate around obstructions independently, preventing the entire limiter from snagging while maintaining extrusion control through the segmented structure
Solution Approach 2:
The extrusion limiter transitions from a static rigid structure to a dynamic segmented structure that can adapt its shape and flexibility in response to well bore conditions, allowing it to flex around obstructions without causing pre-set
2Adaptability or versatility
If the packer element is designed to be repeatedly set and unset for moving between locations, then versatility is improved, but the element becomes more susceptible to pre-set and damage
Solution Approach 1:
Compression springs are pre-installed to provide cushioning force that prevents the packer element from being forced into a pre-set condition during insertion, protecting the element from damage before it is even set at the target location
Solution Approach 2:
The segmented anti-extrusion ring with compression springs creates a preliminary counter-force that opposes any premature expansion or pre-set of the packer element, allowing safe navigation through the well bore before the element is intended to be set
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 inhibits pre-set and extrusion of packer elements, maintaining a reliable fluid seal under hydraulic pressures and navigating through cased well bores without snagging obstructions, thus enhancing the operational reliability of retrievable packers.
Implementation Method 1
a pre-set inhibiting extrusion limiter comprising a stepped cone frustum that supports a plurality of anti-extrusion ring segments held together by a retainer ring that is retained in a retainer ring groove in the respective anti-extrusion ring segments and retains a respective compression spring for each of the respective anti-extrusion ring segments
Data Source
AI summary
A pre-set inhibiting extrusion limiter has a segmented anti-extrusion ring with a plurality of anti-extrusion ring segments supported by a stepped cone frustum. Each ring segment is retained in a run-in condition by a compression spring retained by a retainer ring held in a retainer ring groove in the respective anti-extrusion ring segments. A push ring moves the respective anti-extrusion ring segments from the run-in condition to a packer-set condition in which the anti-extrusion ring segments abut a cone frustum step of the stepped cone frustum.