Wireline Sealing Assembly Multi-Material Seal Members
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Solution Overview
Problem
Existing wireline sealing assemblies in oil and gas wells face challenges in effectively controlling wellbore pressure and minimizing damage to cables due to high forces and pressure changes, leading to extrusion of elastomers and potential cable damage.
Innovation Solution
A wireline sealing assembly with multiple seal members made of different materials, including elastomeric and harder backup sealing elements, which deform radially to contain wellbore pressure while allowing cable movement, featuring a piston-actuated design to control pressure and reduce friction and extrusion risks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single elastomeric seal member is used to seal against the wireline, then the seal can conform to the cable surface and provide pressure containment, but the elastomer is prone to extrusion under high wellbore pressure and causes cable damage
Solution Approach 1:
The seal is divided into multiple seal members (first seal member with elastomeric sealing element, second seal member with harder backup sealing element, and optionally third seal member with even harder sealing element) arranged in series along the wireline. Each seal member contributes to pressure containment while distributing the sealing function across different materials with varying properties, preventing any single material from being overloaded and extruding.
Solution Approach 2:
The sealing system uses composite construction by combining seal members made of different materials with different hardness ratings and resilience characteristics. The elastomeric material provides conformability and sealing, while the harder backup materials provide structural support and resistance to extrusion, creating a composite sealing system that leverages the advantages of each material type.
2Reliability
If high actuating pressure is applied to compress the seal against the wireline, then pressure containment is improved, but friction increases and cable movement becomes difficult
Solution Approach 1:
Different seal members are positioned at different locations along the wireline with different material properties optimized for their specific positions. The elastomeric seal members provide conformability where needed, while harder backup seal members provide structural support in regions requiring extrusion resistance. This local differentiation allows effective sealing without uniformly high friction across the entire cable surface.
Solution Approach 2:
The system changes the material parameters (hardness, resilience) of different seal members to achieve optimal sealing performance. By varying these parameters across the seal assembly rather than using a uniform material, the system achieves pressure containment with reduced overall friction, as the harder materials require less compression force to maintain their sealing geometry.
3Reliability
If a harder backup sealing element is added to support the elastomeric seal, then extrusion resistance is improved, but the seal becomes more complex
Solution Approach 1:
The seal members are arranged in a nested configuration where the second seal member with harder backup sealing element surrounds or supports the first seal member with elastomeric sealing element, and optionally a third seal member with even harder material surrounds the second. This nested arrangement provides extrusion resistance through multiple layers while maintaining a compact structure that does not significantly increase overall device complexity.
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 provides improved control over seal actuation, reduces elastomer extrusion and cable damage, and extends the life of sealing assemblies and cables, enabling use in higher-pressure wells with reduced risk of pressure changes and improved 'nipping' of seals.
Implementation Method 1
the elastomeric sealing element is adapted to deform radially inwards upon the application of axial force
Implementation Method 2
the backup sealing element is formed of a less resilient material... the first and second seal members deform, optionally in a radial direction against the line
Implementation Method 3
the seal is actuated to compress elastomeric sealing elements against the line
Data Source
AI summary
A wireline sealing assembly adapted to seal a line such as wireline or slickline deployed in an oil or gas well has a body to receive a line and a seal adapted to be actuated into sealing engagement with the line to contain wellbore pressure within the well below the actuated seal. The seal comprises first and second seal members, each seal member comprising at least one sealing element, wherein the first and second seal members are formed of different materials. The second seal member may have a greater hardness rating or lower degree of resilience that the first seal member. The first and second seal members may radially deform against the line when the seal is actuated, and the first seal member may radially deform more than the second seal member. The seal may also comprise a third seal member comprising at least one sealing element, wherein the third seal member is formed of a different material to the first and second seal members.