Expandable Backup Ring Radial Expansion for Packer Extrusion
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Solution Overview
Problem
Existing downhole isolation tools face challenges with sealing element extrusion, particularly due to premature expansion and reduced sealing pressure, which can lead to leaks and faulty seals, especially in high-pressure and high-temperature environments.
Innovation Solution
An expandable backup ring design featuring a radially inwardly projecting protrusion pattern with offset outer surface cuts and furrows, which allows for radial expansion without breaking into segments, providing a solid support for the sealing element and minimizing extrusion by maintaining a consistent pressure application.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional segmented backup rings are used, then the sealing element is supported during expansion, but the segments create gaps that allow rubber extrusion and reduce sealing pressure
Solution Approach 1:
The backup ring is divided into multiple segments that can independently expand and conform to the wellbore geometry. Each segment contains embedded reinforcement elements that prevent rubber extrusion while allowing the segment to flex and seal against the casing wall. The segmented design allows the backup ring to adapt to irregular wellbore shapes while maintaining structural integrity and preventing harmful rubber extrusion.
Solution Approach 2:
The backup ring segments are constructed using composite materials combining a flexible polymer matrix with embedded rigid reinforcement elements such as metal wires, fibers, or ribs. This composite structure provides the necessary flexibility for sealing while the reinforcement elements prevent rubber extrusion and maintain structural strength under high pressure and temperature conditions.
2Object-generated harmful factors
If the backup ring is made rigid to prevent extrusion, then sealing pressure is maintained, but the ring cannot expand to conform to irregular wellbore shapes
Solution Approach 1:
The backup ring is designed as a dynamic structure that transitions from a compressed transport state to an expanded operational state. The ring segments are initially compressed together to fit within the deployment device, then expand radially outward upon deployment to conform to the wellbore geometry. This dynamic expansion allows the backup ring to adapt to irregular wellbore shapes while maintaining the structural rigidity needed to prevent rubber extrusion.
Solution Approach 2:
Different regions of the backup ring segment have different mechanical properties optimized for their specific functions. The outer surface features rigid reinforcement elements for extrusion prevention, while the inner surface has a softer, more compliant material for conforming to the wellbore. The segment structure itself provides localized flexibility at the joints while maintaining overall structural integrity.
3Adaptability or versatility
If the backup ring expands prematurely during running, then it can conform to the wellbore, but it loses structural integrity and creates extrusion paths
Solution Approach 1:
The backup ring segments are pre-configured with expansion features and reinforcement elements in their compressed transport state. The segments are designed to maintain their structural integrity and prevent rubber extrusion even before full expansion.预埋的展开特征和加强元素在压缩运输状态下就已经配置好，确保在完全展开前就能维持结构完整性并防止橡胶挤出。
Solution Approach 2:
The backup ring segments are nested within each other or within a deployment device during transport, with each segment containing reinforcement elements and expansion features. This nested configuration allows the segments to be compacted for insertion while maintaining their structural integrity and preventing premature expansion. The nesting arrangement also provides mechanical约束 that prevents early activation.
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 effectively prevents rubber extrusion, maintains sealing pressure, and is robust enough for use in demanding applications like openhole packers and liner top packers, ensuring reliable containment and zero extrusion gap once set.
Implementation Method 1
allows for radial expansion without breaking into segments
Data Source
AI summary
An expandable backup ring includes an outer surface, an inner surface having a plurality of protrusions projecting radially inwardly, and a plurality of segments, the segments defined by a plurality of outer surface cuts. The plurality of outer surface cuts extends radially inwardly from the outer surface and partially into each of the plurality of protrusions.