Retrievable Bridge Plug with Retractable Backup Rings
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Solution Overview
Problem
Conventional packer and slip systems in bore applications face limitations in transitioning from small to large diameters without compromising sealing or anchoring capabilities, and they have poor load ratings and restricted movement, making them unsuitable for operations requiring significant diameter changes.
Innovation Solution
A packer assembly with a packer mandrel, packing element, upper and lower recovery sleeves, and backup assemblies that allow axial compression and radial expansion, enabling the packing element to transition from a small to a large diameter for effective sealing and anchoring, and a retrieval mechanism for easy removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the packing element is made with a smaller initial outer diameter to facilitate installation through bore restrictions, then ease of installation is improved, but sealing capability deteriorates
Solution Approach 1:
The packing element is designed to dynamically change its diameter from a smaller initial state during installation to a larger expanded state during operation. The element is compressed axially during setting, causing it to expand radially to achieve sealing contact with the bore wall, thereby maintaining both ease of installation and sealing capability at different operational stages
Solution Approach 2:
The packing element undergoes parameter changes in its dimensional properties, specifically transitioning from a smaller initial outer diameter to a larger expanded diameter. This parameter transformation allows the element to fit through restrictions during installation while achieving adequate sealing pressure and contact area when expanded in the bore
2Strength
If slip members are extended from a small diameter to a large diameter to improve anchoring capability, then anchoring strength is improved, but load rating deteriorates
Solution Approach 1:
The slip members are designed to dynamically extend from a retracted position to an extended position, changing their radial dimension from small to large. This dynamic transformation allows the slip members to engage with the bore wall for anchoring while maintaining structural integrity and load-bearing capacity through the controlled extension mechanism
Solution Approach 2:
The slip system is segmented into multiple slip members that can independently extend and engage with the bore wall. This segmentation allows the anchoring function to be distributed across multiple elements, improving overall anchoring capability while maintaining individual member load ratings
3Strength
If slip members are extended to improve anchoring capability, then anchoring strength is improved, but device complexity increases
Solution Approach 1:
The slip members are merged with the packer assembly structure, integrating the anchoring function into the existing packer body. This integration reduces overall device complexity by combining multiple functions into a unified structure while maintaining the slip members' ability to extend and provide anchoring capability
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 enables the packer assembly to maintain sealing and anchoring capabilities while allowing for diameter transitions, improving load ratings and facilitating easy retrieval by retracting the backup rings, thus overcoming the limitations of conventional systems.
Implementation Method 1
The packing element may be made out of a deformable material, such as an elastomer, to a prescribed initial length and initial outer diameter. The packing element may be set in a bore by the application of axial compression, thereby reducing the length of the packing element, and causing the packing element to deform radially outward into sealing contact with the surrounding bore.
Implementation Method 2
A retrieval mechanism is provided that may include a retrieval sleeve and a bearing assembly. The bearing assembly may include a retrieval bearing and a backup ring bearing. The retrieval bearing may be disposed between the retrieval sleeve and the backup ring assembly, and the backup ring bearing may be disposed between the retrieval sleeve and the backup ring assembly. These bearings reduce friction to facilitate smooth movement during retrieval operations.
Data Source
AI summary
A packer assembly includes a packer mandrel and a packing element disposed about the packer mandrel. An upper recovery sleeve is disposed about the packer mandrel and extending between the packer mandrel and an upper end of the packing element, and a lower recovery sleeve is disposed about the packer mandrel and extending between the packer mandrel and a lower end of the packing element. An upper backup assembly is movably disposed about the upper recovery sleeve and adjacent to the upper end of the packing element. A lower backup assembly is movably disposed about the lower recovery sleeve. The lower backup assembly has a lower backup ring assembly configured to enclose an outer surface of the lower end of the packing element. A retrieval sleeve is selectively movable relative to the lower backup ring assembly and configured to at least partially retract the lower backup ring assembly.