Eutectic Alloy Plug and Heater Assembly for Well Abandonment
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Solution Overview
Problem
Existing methods for plugging abandoned oil and gas wells, such as using cement or resin, are unreliable and prone to leaking, leading to costly re-plugging efforts.
Innovation Solution
Deployment and recovery of eutectic alloy plugs, specifically bismuth-containing alloys, using a plug/heater assembly that allows for in-situ control and retrieval without drilling or explosives, utilizing a releasable connection mechanism between the plug and heater to ensure a tight seal within the well.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If cement or resin is used to plug wells, then the plugging process is simple, but the reliability of the seal is poor and leaking occurs
Solution Approach 1:
The invention changes the physical parameters of the sealing material by using phase-change materials (PCM) that undergo solid-liquid phase transitions at controlled temperatures. The PCM is injected in liquid form and then solidifies to form a reliable seal, combining ease of injection with high sealing reliability. This resolves the contradiction by transforming the material state rather than relying on simple cementing processes.
Solution Approach 2:
The invention utilizes phase transitions of phase-change materials as the core sealing mechanism. The PCM transitions from liquid to solid state upon contact with the wellbore environment or through controlled cooling, creating a reliable mechanical seal. This phase transition mechanism provides both ease of injection (liquid state) and high seal reliability (solid state), directly resolving the technical contradiction.
2Device complexity
If traditional plugging methods are used, then equipment requirements are minimal, but re-plugging is required due to leaking
Solution Approach 1:
The invention changes the fundamental parameters of the sealing approach by using temperature-controlled phase-change materials instead of traditional cement or resin. This allows for reliable sealing with relatively simple injection equipment, as the PCM self-solidifies through phase transition rather than requiring complex curing processes or additional equipment.
Solution Approach 2:
The phase-change material acts as a consumable sealing agent that is injected, solidifies to form the seal, and remains in place permanently. The material itself is relatively simple and cost-effective compared to repeated plugging operations, providing long-term reliability without requiring complex reusable equipment systems.
3Reliability
If a reliable seal is achieved using phase-change materials, then leak prevention is improved, but the process requires heating and phase change control
Solution Approach 1:
The phase-change materials are designed to self-solidify through passive heat dissipation to the wellbore environment without requiring active cooling systems. The PCM utilizes the temperature differential between the injected material and the wellbore as a natural heat sink, eliminating the need for complex active cooling equipment while maintaining reliable seal formation.
Solution Approach 2:
The invention optimizes the melting point and phase transition temperature of the PCM to match the wellbore temperature conditions. By carefully selecting PCMs with transition temperatures slightly above ambient wellbore temperature, the system achieves reliable sealing through passive heat dissipation, minimizing the need for active heating or cooling control systems.
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 a reliable and cost-effective method for plugging and re-opening wells, ensuring a strong seal without the need for extensive equipment, reducing the risk of leaks and re-plugging expenses.
Implementation Method 1
makes use of the fact that such alloys contract upon melting and expand again when they re-solidify
Implementation Method 2
the alloy expands to form a tight seal with the walls of the well
Implementation Method 3
heated until it melts and 'slumps'
Implementation Method 4
heated until it melts
Data Source
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AI summary
Apparatus, in the form of a eutectic alloy plug and a deployment heater are provided. The plug and the deployment heated are provided with means for releasably retaining the deployment heater within a cavity in the plug. The nature of the retaining means is such that once the plug is secured in a well the heater can be recovered without the plug. An extraction heater, which is also receivable within the cavity of the plug, is provided to re-melt the eutectic alloy and thus enable the extraction of the plug from a well. Various method of plugging abandoned wells are made possible by the control that the provided apparatus gives.