Thermite Casing Removal Tool for Rigless Well Abandonment
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Solution Overview
Problem
Current methods for abandoning oil and gas wells, such as mechanical milling and explosive perforation, are inefficient and prone to leakage due to casing deterioration, requiring heavy equipment and not addressing fissures caused by casing degradation over time.
Innovation Solution
A casing removal tool utilizing a thermite fuel mixture that initiates an exothermic reaction to melt, vaporize, and disintegrate wellbore casing sections, allowing for rigless removal without the need for milling or high-pressure equipment, using a densely packed nozzle array and orientation tools for precise orientation and deployment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If mechanical milling techniques are used to remove casing, then the casing can be removed from the wellbore, but the operation is slow and may take a month or more to complete
Solution Approach 1:
The patent replaces the mechanical milling system with a thermal system. A thermite-based cutting tool is deployed that uses exothermic chemical reactions to melt and sever the casing, eliminating the need for mechanical drilling and milling operations that require heavy rigs and take months to complete.
Solution Approach 2:
The invention changes the operational parameters from mechanical force and slow rotational milling to high-temperature thermal energy concentration. The thermite reaction generates temperatures sufficient to rapidly melt steel casing, transforming the removal process from a slow mechanical operation to a rapid thermal cutting process.
2Productivity
If mechanical milling is used to remove outermost casing, then casing removal is achieved, but heavy rigs and large milling drills are required at the surface
Solution Approach 1:
The patent replaces the heavy mechanical milling system with a compact thermal cutting device. The thermite-based tool can be deployed via wireline or coiled tubing, eliminating the need for heavy surface rigs and large milling drills while achieving the same casing removal function.
Solution Approach 2:
The invention extracts the cutting function from the heavy surface milling equipment and concentrates it in a small, deployable downhole tool. The thermite-based cutting mechanism is contained within a compact device that can be lowered into the wellbore, separating the cutting capability from the heavy support infrastructure.
3Ease of operation
If explosive perforation is used to create flow paths, then holes are formed in the casing, but adequate flow paths are difficult to achieve and cement may not completely seal the annulus
Solution Approach 1:
The patent replaces explosive perforation with a controlled thermal cutting process. The thermite-based tool creates clean, precise openings through the casing by melting the metal, providing reliable flow paths for cement without the variability and potential failure modes of explosive techniques.
4Reliability
If cement squeeze is used to force cement into the wellbore, then cement fills cracks in the casing or surrounding formation, but heavy equipment capable of producing high pressures is still required
Solution Approach 1:
The invention extracts the high-pressure generation function from heavy surface equipment and relocates it to a compact downhole thermite-based device. The cutting tool creates openings that allow cement to flow naturally or with minimal pressure, eliminating the need for heavy pressurizing equipment while achieving effective sealing.
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 efficient and long-term sealing of wellbores by removing casing sections uniformly, reducing the risk of leakage and contamination, and eliminating the need for heavy equipment, thus minimizing time and financial resources.
Implementation Method 1
a tubular body configured to contain a thermite fuel mixture configured to initiate into a molten thermite fuel
Implementation Method 2
the molten thermite fuel impinges onto the casing and melts, vaporizes, and/or disintegrates the casing
Implementation Method 3
The nozzle array can be configured to impinge the molten thermite fuel onto a section of the wellbore casing
Implementation Method 4
the molten thermite fuel impinges onto the casing and melts, vaporizes, and/or disintegrates the casing
Implementation Method 5
a tubular body configured to contain a thermite fuel mixture configured to initiate into a molten thermite fuel
Data Source
Figure 1
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Figure 4
AI summary
Systems and methods for removing casing from a wellbore including a casing removal tool that includes a tubular body configured to contain a thermite fuel mixture configured to initiate into a molten thermite fuel. The casing removal tool also includes a nozzle array having a plurality of nozzles positioned on an external surface of the tubular body. The nozzle array is configured to impinge the molten thermite fuel from within the tubular onto the wellbore casing. The casing removal tool also includes an orientation lug configured to anchor into a downhole orientation tool.