Repairable Seal Assemblies Using Eutectic Alloy Transition Rings
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Solution Overview
Problem
Conventional seal assemblies in subterranean wellbores require costly and time-consuming rig operations for repair when seal stacks fail, leading to tubing-to-annulus communication and compromised wellbore integrity, with no in-situ repair options available.
Innovation Solution
A repairable seal assembly featuring a eutectic metal alloy transition ring that can be melted using a heater to form a metal-to-metal seal, allowing for in-situ repair without the need for a rig operation, by changing its state from solid to liquid and back to solid to seal against the receptacle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional seal assemblies are used with multiple seal stacks, then sealing reliability is improved, but repair complexity increases when seal stacks fail requiring rig workover
Solution Approach 1:
The transition ring changes its physical state from solid to liquid and back to solid through temperature control. During installation, the transition ring is heated above the melting point of the eutectic alloy to become liquid, allowing it to be injected into the seal assembly. When it cools below the melting point, it solidifies to form a metal-to-metal seal, providing a repair mechanism that restores sealing function without requiring rig workover.
Solution Approach 2:
The eutectic metal alloy transition ring utilizes phase transition between solid and liquid states at a controlled melting point. This phase change enables the transition ring to be easily introduced in liquid form and then solidify to create a permanent or contingent seal, providing an in-situ repair capability that eliminates the need for complex rig operations while maintaining high sealing reliability.
2Reliability
If rig workover is performed to replace failed seal assembly, then wellbore integrity is restored, but production time is lost and costs increase
Solution Approach 1:
The seal assembly includes a self-contained repair mechanism where the transition ring can be activated in-situ to restore sealing function. The system uses its own components (transition ring, heater, and eutectic alloy) to perform the repair without requiring external rig intervention, thereby maintaining wellbore integrity while minimizing production time loss.
Solution Approach 2:
The transition ring is pre-installed within the seal assembly in a dormant state, positioned to provide backup sealing capability. This preliminary preparation allows for rapid activation and repair when seal stacks fail, eliminating the need for time-consuming rig workover and production shutdown.
3Ease of repair
If eutectic metal alloy transition ring is added for in-situ repair, then ease of repair is improved, but device complexity increases
Solution Approach 1:
The seal assembly is segmented into distinct functional components: seal stacks for primary sealing, a transition ring for repair, anchors for positioning, and a heater for activation. This segmentation allows each component to perform its specific function independently, making the overall system manageable despite the added repair capability.
Solution Approach 2:
The transition ring serves multiple functions: it acts as a spacer during installation, provides backup sealing capability, and can be activated to create a metal-to-metal seal when seal stacks fail. This multi-functionality reduces the need for separate components, thereby limiting the increase in device complexity while providing in-situ repair capability.
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
Enables immediate and permanent or contingent sealing, deferring and reducing workover costs, allowing continued production and scheduling of optimal repair operations, thus maintaining wellbore integrity and production targets.
Implementation Method 1
The one or more metal rings are made of a eutectic material (e.g., a metal alloy designed to have a relatively low melting point that is above a reservoir temperature of the wellbore). The low melting point allows the eutectic material to be easily melted without damaging the other metal components (for example, typically steel components) in the completion tubing.
Implementation Method 2
the one or more metal rings are in a solid state at relatively low temperatures and in a liquid state at temperatures above the melting point of the eutectic material
Implementation Method 3
the one or more metal rings are in a solid state at relatively low temperatures and in a liquid state at temperatures above the melting point of the eutectic material
Implementation Method 4
In a liquid state, the eutectic material flows downward along the cylindrical body, and spreads radially from the cylindrical body to the inner diameter of the receptacle. The eutectic material cools from the liquid state to a solid state in which the eutectic material forms a metal ring with an outer diameter that is about equal to the inner diameter of the receptacle to effect a metal-to-metal seal
Data Source
AI summary
A repairable seal assembly for deployment at a wellbore includes an elongate body, a first seal carried by the elongate body and configured to seal against an adjacent surface, and a transitional component carried by the elongate body. The transitional component is adjustable from a first configuration in which the transitional component defines a gap between the transitional component and the adjacent surface to a second configuration in which the transitional component contacts the adjacent surface to form a second seal at the adjacent surface.