Well Casing Plugging Sleeve for Lateral Metal Perforation Sealing
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Solution Overview
Problem
Current methods for plugging and sealing subterranean wells, particularly using metal plugs, face inefficiencies due to limited capacity for lateral filling of perforations and the inability to reuse heater tools effectively, leading to increased operation costs and time.
Innovation Solution
A plugging device with a cylindrical sleeve containing thermite that is ignitable by an ignition mechanism, allowing for the melting of meltable plugging material to flow laterally into perforations, and the tool's retrievable design for reconditioning and reuse.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If cement is used for plugging wells, then it can be pumped through perforations, but it mixes with drilling mud or downhole fluids causing early failure due to channeling
Solution Approach 1:
The invention changes the material parameter from cement to molten metal (such as eutectic alloys), which fundamentally alters the physical and chemical properties. The molten metal maintains its integrity when contacting drilling mud or downhole fluids, preventing the channeling issue that plagues cement plugs while achieving reliable well plugging.
Solution Approach 2:
The invention uses composite or alloy materials (eutectic metals or solder) that combine multiple elements to achieve a low melting point while maintaining structural integrity. This composite approach allows the plugging material to remain stable and resistant to channeling when exposed to various downhole fluids.
2Reliability
If metal plugs are used to seal perforations, then they resist mixing with fluids, but the heater tool cannot be retrieved for reuse
Solution Approach 1:
The invention divides the tool into separable components: the heater assembly and the plugging material. The heater can be detached and retrieved for reuse, while the molten metal plug remains in the well to perform its sealing function. This segmentation allows the expensive heater component to be reused while the consumable plugging material stays in place.
Solution Approach 2:
The invention implements a strategy where the heater tool is recovered and reused, while the molten metal plugging material is discarded into the well. This recovery approach reduces operational costs and time by eliminating the need to retrieve or replace the expensive heater assembly after each plugging operation.
3Reliability
If traditional plugging methods are used, then they can seal wells, but they require significant material and time
Solution Approach 1:
The invention utilizes phase transition (melting and solidification) of molten metal to achieve efficient plugging. The metal is heated to a liquid state for easy injection and distribution into perforations, then solidifies to form a reliable seal. This phase transition allows complete filling of perforations with minimal material waste, as the molten metal flows into all cavities before solidifying.
Solution Approach 2:
The invention replaces mechanical pumping methods with thermal processing. Instead of mechanically forcing cement through perforations, the system uses heat to melt the plugging material, which then flows into perforations under its own weight and capillary action, requiring significantly less material and energy.
4Ease of operation
If cement is used for plugging, then it can be injected into wells, but it is difficult to pump through perforations in joints
Solution Approach 1:
The invention uses phase transition from solid to liquid state to overcome pumping difficulties. The molten metal flows easily through perforations and joint gaps without requiring high pumping pressures, yet still achieves complete and precise filling of the target areas. The liquid state allows the material to conform to irregular geometries that would be difficult to fill with pumped cement.
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 enables efficient sealing of wells by allowing larger volumes of molten material to be melted and laterally displaced into perforations, reducing operation time and material usage, while the retrievable heater minimizes costs and facilitates repeat treatments.
Implementation Method 1
a heater that comprises thermite that is coupled to and ignitable by an ignition mechanism so as to melt the meltable plugging material
Implementation Method 2
allowing for the melting of meltable plugging material to flow laterally into perforations
Data Source
AI summary
This disclosure describes a device and method of sealing perforations on a well casing inside a subterranean well. The device comprises a generally cylindrical sleeve having an open top and a closed bottom; a heater located inside the sleeve, the heater comprising a thermite mixture; an ignition mechanism that ignites the thermite mixture upon actuation; and a string connected to the heater ignition and detachably engages the sleeve. The method comprises lowering a body of meltable plugging material into the well casing near the perforations; lowering the plugging device into the well casing immediately on top of the body of meltable plugging material; melting the meltable plugging material by igniting the thermite thereby transferring heat to the body of meltable plugging material; forcing the molten plugging material into the perforations by pushing the plugging tool further downhole; cooling the plugging tool and the plugging material until the plugging material solidifies; disengaging the tubing string from the sleeve and retrieving the tubing string with the heater; and removing the sleeve and bismuth remaining in the well casing, but not in the perforations.