Segmented Backup Ring for Frac Plug Sealing and Easy Milling
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Solution Overview
Problem
Existing frac plugs require precise and expensive components for sealing, leading to challenges in forming a reliable seal and subsequent difficulties in milling them out after fracturing operations.
Innovation Solution
A frac plug design featuring a mandrel, sealing element, backup ring, cone, and slip assembly with segments and buttons that expand radially to anchor securely to the casing, preventing sealing element extrusion and enabling easy removal post-fracturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If precise and expensive components are used for sealing, then sealing reliability is improved, but manufacturing cost and device complexity increase
Solution Approach 1:
The backup ring is divided into multiple segments separated by slots, allowing each segment to independently deform and engage with the casing. This segmentation provides reliable anchoring through multiple engagement points while simplifying the overall structure compared to a solid backup ring, resolving the contradiction between sealing reliability and device complexity.
Solution Approach 2:
The backup ring segments are designed to change their physical state from a compressed, stored configuration to an expanded, engaged configuration during deployment. This parameter change allows the segments to reliably engage with the casing interior while maintaining a compact form factor, addressing both reliability and complexity concerns.
2Reliability
If precise and expensive components are used for sealing, then sealing reliability is improved, but milling out difficulty increases
Solution Approach 1:
The segmented backup ring can be milled out in sections through the slots, making removal significantly easier than a solid backup ring. Each segment can be independently accessed and removed, reducing the time and complexity of the milling out process while maintaining sealing reliability during operation.
Solution Approach 2:
The slots in the backup ring segments provide extraction paths that allow milling tools to access and remove the backup ring components. This design feature directly addresses the milling out difficulty by providing built-in access channels, resolving the contradiction between sealing reliability and ease of removal.
3Reliability
If a solid backup ring is used to prevent sealing element extrusion, then sealing reliability is improved, but device complexity and cost increase
Solution Approach 1:
The backup ring is segmented into multiple sections with slots between them, maintaining the function of preventing sealing element extrusion while reducing material usage and structural complexity. The segments collectively provide the necessary retention force without requiring a solid continuous structure.
Solution Approach 2:
The backup ring segments are designed as flexible components that can deform and conform to the casing interior, providing reliable sealing element retention through elastic deformation rather than rigid structural support. This flexibility reduces the required structural complexity while maintaining retention reliability.
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 design ensures a reliable seal during fracturing operations while allowing easy milling out of the frac plug post-operation, reducing costs and complexity.
Implementation Method 1
a slip assembly that, when the frac plug is set within the cased well, travels along the cone and expands radially to allow buttons disposed in slips of the slip assembly to engage the casing of the well
Implementation Method 2
The sealing element may be formed of an elastomeric material or metal material which is deformed in a radially outward direction until forming a permanent seal with the inside surface of the casing
Data Source
AI summary
A backup ring for a frac plug. The backup ring may include a plurality of segments defined by a plurality of slots, where each segment is defined by a sequential pair of the plurality of slots. The backup ring may also include a plurality of buttons, wherein at least one button is disposed on each segment. The backup ring creates a backup anchor for the sealing element and reduces or prevents extrusion of the sealing element.