Downhole Heat Tool Seals Microannulus via Melted Fill Material
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Solution Overview
Problem
Microannuli in wellbores compromise zonal isolation by allowing undesirable fluid flow between geological zones, and existing remediation techniques are resource-intensive and often temporary, as they may not effectively seal the gaps due to casing expansion and contraction.
Innovation Solution
A downhole tool with a heat generation device is used to melt a fill material, which flows through perforations into microannuli, solidifies to seal the gaps, and excess material is removed, restoring zonal isolation without expanding the casing diameter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing remediation techniques are used to seal microannuli, then zonal isolation may be temporarily improved, but the solution is resource-intensive and temporary due to casing expansion and contraction
Solution Approach 1:
The patent changes the physical state of the fill material from solid to molten using heat generation, allowing it to flow into and seal the microannulus. This phase change enables the material to adapt to the annulus geometry and create a reliable seal that withstands casing expansion and contraction, resolving the contradiction between temporary sealing and long-term reliability.
Solution Approach 2:
The patent utilizes phase transition of the fill material (solid to liquid to solid) to achieve effective sealing. The material is melted to flow into the microannulus and then solidifies to form a permanent seal, providing long-term zonal isolation without the temporary nature of conventional remediation techniques.
2Reliability
If conventional remediation methods are applied, then some sealing may be achieved, but extensive resource allocation is required and the solution is not effective against casing movement
Solution Approach 1:
The patent applies local quality by concentrating the fill material and heat generation at the specific location of the microannulus rather than using extensive resources throughout the wellbore. The downhole tool delivers molten material precisely where needed, achieving effective sealing with minimal resource allocation and eliminating the need for widespread intervention.
Solution Approach 2:
The patent employs self-service by using the heat generation device to melt the fill material on-site, allowing the material to self-flow into the microannulus through gravity and pressure differential. This eliminates the need for external resource intervention and enables the system to seal itself using locally generated energy.
3Reliability
If the casing diameter is expanded to seal microannuli, then zonal isolation may be improved, but the casing structure is compromised and cannot be reused
Solution Approach 1:
The patent replaces the mechanical approach of expanding the casing with a thermal-chemical process. Instead of mechanically forcing the casing to seal the microannulus (which compromises structural integrity), the system uses heat to melt fill material that flows into the annulus and solidifies to create the seal, preserving casing strength and enabling reuse.
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 method effectively seals microannuli, restoring pressure integrity and zonal isolation without the need for extensive resource allocation, ensuring long-term prevention of fluid flow between zones.
Implementation Method 1
activating the heat generation device to melt a fill material at the location of interest such that the fill material flows through the perforations into one or more voids
Implementation Method 2
deactivating the heat generation device to facilitate solidification of the fill material in the one or more voids and sealing of the microannulus
Data Source
AI summary
A method for remediating a microannulus in a cased wellbore may include conveying a downhole tool into the cased wellbore to a location of interest. The location of interest may include one or more perforations in a casing and a microannulus. The downhole tool may include a heat generation device. The method may also include activating the heat generation device to melt a fill material at the location of interest such that the fill material flows through the perforations into one or more voids, including the microannulus, in or around cement disposed between the casing and the cased wellbore. Additionally, the method may include deactivating the heat generation device to facilitate solidification of the fill material in the one or more voids and sealing of the microannulus.