Extrusion Limiting Ring for Wellbore Isolation Seals
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Solution Overview
Problem
Wellbore isolation devices face challenges in maintaining a seal at elevated pressures and temperatures due to material creep and extrusion through small gaps, leading to reduced sealing capacity and potential fluid leakage.
Innovation Solution
The implementation of an extrusion limiting ring with a scarf cut that expands radially with the sealing element, preventing material extrusion by moving from a contracted state around the sealing element to an expanded state about the outer radial surface of the slip wedge, thereby sealing gaps and maintaining the seal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the sealing element material is used to form the seal at elevated pressures and temperatures, then the sealing capacity is initially adequate, but the material creeps and extrudes through small gaps reducing sealing capacity
Solution Approach 1:
The extrusion limiting ring serves as an intermediary component between the sealing element and the surrounding structure. It prevents direct contact and interaction between the sealing element material and the gaps, thereby eliminating the extrusion pathway while maintaining the sealing function.
Solution Approach 2:
The extrusion limiting ring is designed with a scarf cut that divides it into segments capable of relative movement. This segmentation allows the ring to expand radially in response to sealing element expansion while maintaining its extrusion prevention function throughout the expansion process.
2Reliability
If the sealing element is expanded radially outward to seal the wellbore, then the sealing engagement is achieved, but gaps are created that allow material extrusion
Solution Approach 1:
The extrusion limiting ring acts as a mediator that fills and seals the gaps created during radial expansion. It positions itself between the sealing element and the external environment, preventing material from entering the gaps while allowing the sealing element to achieve its sealing engagement.
Solution Approach 2:
The extrusion limiting ring is pre-positioned about the sealing element before expansion occurs. In its contracted state, it is ready to prevent extrusion. Upon expansion, it transitions to the expanded state, maintaining its protective function throughout the process rather than creating gaps first and then sealing them.
3Reliability
If the extrusion limiting ring is designed to prevent material extrusion, then sealing capacity is maintained, but the device complexity increases
Solution Approach 1:
The extrusion limiting ring is designed as a thin, flexible annular body that can radially expand and contract. This flexible shell structure provides the extrusion prevention function without requiring complex mechanical components, multiple moving parts, or sophisticated control systems.
Solution Approach 2:
The extrusion limiting ring is designed to be dynamic rather than static. It can transition between contracted and expanded states in response to the sealing element's expansion, adapting its configuration to the operational requirements while maintaining a simple overall structure.
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
This solution effectively prevents material extrusion into radial and axial gaps, enhancing the sealing capacity and reducing fluid leakage in high-pressure and temperature downhole environments.
Implementation Method 1
the wellbore isolation device is actuated to radially expand the sealing element and thereby seal the wellbore at the desired location
Implementation Method 2
the extrusion limiting ring is disposed about an outer radial surface of the lower slip wedge... preventing material extrusion into axial gaps formed between angularly adjacent slip segments
Data Source
AI summary
A wellbore isolation device includes an elongate mandrel, a sealing element carried by the mandrel, and a slip wedge positioned about the mandrel axially adjacent the sealing element and providing an outer radial surface. A set of slip segments is circumferentially disposed about the mandrel and at least a portion of the slip wedge. An extrusion limiting ring has an annular body that provides a first axial end, a second axial end, and a scarf cut extending at least partially between the first and second axial ends. The extrusion limiting ring is movable between a contracted state, where the extrusion limiting ring is disposed about the sealing element, and an expanded state, where the extrusion limiting ring is disposed about the outer radial surface of the lower slip wedge.