Downhole Packer Element Spacer Design for Extrusion Control
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Solution Overview
Problem
Conventional packers for high pressure and high temperature applications often experience over-extrusion and incomplete sealing due to thick metal fold back rings, leading to potential failure and leakage, especially during thermal cycling.
Innovation Solution
A downhole apparatus featuring compressible elastomeric elements with spacers and fold back rings that expand radially to seal against the surrounding surface, where the spacers' extensions and cylindrical lips delay the compression of outer sealing members to prevent over-extrusion and enhance sealing, allowing for better square-off and pack-off during setting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If thick metal fold back rings are used to contain elastomeric elements, then extrusion prevention is improved, but over-extrusion occurs during setting and complete square-off is not achieved
Solution Approach 1:
The packer element is divided into multiple elastomeric elements (inner and outer) separated by spacers, with fold back rings positioned at strategic locations to contain specific segments. This segmentation allows each ring to focus on containing a specific elastomeric element, improving containment effectiveness while reducing the overall thickness required.
Solution Approach 2:
Metal spacers are introduced as intermediary elements between the inner and outer elastomeric elements. These spacers serve as mediators that provide structural support and help distribute forces, enabling the fold back rings to achieve complete square-off without requiring excessive thickness.
2Ease of operation
If metal fold back rings are made thin to allow easier expansion, then setting ease is improved, but the rings become fragile and damage-prone
Solution Approach 1:
The packer element combines metal fold back rings with elastomeric elements and metal spacers to create a composite structure. The metal components provide the necessary strength and rigidity to prevent ring damage, while the elastomeric elements provide flexibility for easy expansion during setting.
3Ease of manufacture
If maximum temperature rating is reduced to simplify design, then manufacturing complexity is reduced, but application versatility is limited
Solution Approach 1:
The use of metal spacers and fold back rings creates a composite structure that can withstand higher temperatures. The metal components maintain their mechanical properties at elevated temperatures, allowing the packer element to be used in high-temperature applications without requiring complex cooling or material substitution designs.
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 reduces the risk of elastomer over-extrusion and improves sealing characteristics by ensuring complete expansion and square-off of fold back rings, enabling reliable operation at higher temperatures with lower setting forces and reduced leakage.
Implementation Method 1
The first element is disposed on the apparatus and is compressible longitudinally to expand radially outward and seal against the surrounding surface
Data Source
Figure 1
Figure 2A~2B
Figure 3A~3B
AI summary
A device and method control the radial expansion of a compressible sealing element on a downhole tool. The tool is deployed adjacent a surrounding surface downhole. The tool has a sealing element with inner and outer members separated by spacers. Inside ends of the outer members overlap extension or lips on the spacers, and fold back rings toward the outer ends of the outer members at least partially limit expansion. To radially expand the sealing element on the downhole tool to seal against the surrounding surface, longitudinally compressions is applied against the sealing element. The fold back rings are expanded initially in this process by using the extensions of the spacers overlapped by the outer members of the sealing element. This allows the fold back rings to square/pack off fully against the surrounding surface during setting and can prevent extrusion of the sealing element over the ends of the fold back rings.