Slip-Deployed Anti-Extrusion Backup Ring for Packer Sealing
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Solution Overview
Problem
Existing packer devices fail to effectively prevent or reduce the axial extrusion of deformable elastomeric packer elements in wellbores, as current backup rings do not adequately secure the packer elements during radial expansion.
Innovation Solution
The implementation of radially expandable anti-extrusion backup rings, which are energized by a slip assembly or an annular spring mechanism, ensuring mechanical contact with the surrounding tubular to prevent extrusion, utilizing materials like annealed steel or non-metallic composites for enhanced rigidity and durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional backup ring is used to prevent extrusion of the packer element, then the packer element is partially protected, but the backup ring fails to effectively prevent axial extrusion during radial expansion
Solution Approach 1:
The backup ring is designed to transition from an initial configuration to an expanded configuration during packer setting. The radially expandable backup ring changes its geometry dynamically - starting as a less intrusive structure and expanding to provide enhanced extrusion prevention as the packer element expands, thereby improving reliability without excessive initial complexity
Solution Approach 2:
The radially expandable backup ring is positioned within or adjacent to the packer element assembly, allowing it to be nested in the initial state and then expand outward to engage the borewall. This nesting approach allows the backup ring to provide effective extrusion prevention while maintaining a compact initial profile
2Strength
If the backup ring is made rigid to prevent extrusion, then extrusion resistance improves, but the backup ring cannot adapt to radial expansion of the packer element
Solution Approach 1:
The backup ring incorporates radial expandability, allowing it to transition from a compact initial state to an expanded state that provides both rigidity for extrusion resistance and adaptability for packer element expansion. The dynamic expansion ensures the backup ring maintains strength while accommodating radial movements
Solution Approach 2:
The backup ring's physical parameters (particularly its radial dimension) are changed during the setting process. By expanding radially, the backup ring increases its contact pressure against the packer element and borewall, thereby improving extrusion resistance while adapting to the expanded state of the packer element
3Reliability
If the backup ring is expanded radially outwardly by the slip assembly, then mechanical contact with the surrounding tubular is achieved, but the device complexity increases
Solution Approach 1:
The backup ring expansion mechanism is combined with the slip assembly setting mechanism. The same radial expansion force that sets the slip assembly also expands the backup ring, merging two functions into a single operational sequence. This reduces overall device complexity by eliminating the need for separate expansion mechanisms
Solution Approach 2:
The backup ring is designed to expand automatically as a result of the slip assembly setting process. The radial expansion force generated by the slip assembly against the cone automatically energizes the backup ring without requiring additional components or actions, allowing the backup ring to serve itself through the existing setting mechanism
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 prevents or reduces axial extrusion of the packer elements by ensuring a secure mechanical contact between the backup rings and the surrounding tubular, maintaining the packer element's sealing integrity during radial expansion.
Implementation Method 1
the slip element urges the backup ring into mechanical or intimate contact with a surrounding tubular when the slip element is set against the surrounding tubular
Implementation Method 2
the slip element urges the spring into a wedged position between the cone and the surrounding tubular so that the wedged spring acts as backup ring
Data Source
AI summary
Arrangements and packer devices having anti-extrusion backup rings that are expanded radially outwardly by a setting mechanism that lies proximate the elastomeric packer element that is being protected against extrusion. The setting mechanism can be a slip assembly that has a radially expandable slip element.