Single Trip Alloy Seal Milling System
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Solution Overview
Problem
Current technologies for well bore repair, such as casing patches, scab liners, and metal alloy plugs, often require multiple trips and can result in well bore restrictions, compromised flow areas, and failure due to corrosion or pressure differentials.
Innovation Solution
A downhole tool assembly system that combines a tubular heater with an exothermic chemical reaction heat source, a mill, and a tubular mandrel to deploy alloy plugs and/or seals in a single trip, using eutectic or bismuth-based alloys that melt at 300°C or below, allowing for the formation and subsequent milling of a plug or seal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple trips are used for well bore repair operations, then repair integrity can be improved, but time consumption and operational costs increase
Solution Approach 1:
The patent combines multiple repair operations (seal setting and milling) into a single integrated tool assembly that can be deployed in one trip. The tool assembly includes a heater for melting alloy seal material and a mill for removing the seal, both contained within the same downhole device that operates sequentially during a single well intervention trip.
Solution Approach 2:
The downhole tool assembly performs multiple functions: it deposits alloy seal material, melts the seal to set it in place, and then mills through the seal to restore flow. This multi-functional device eliminates the need for separate tools and multiple trips, achieving both sealing and milling operations in one deployment.
2Reliability
If alloy seals are used for well bore repair, then seal integrity can be improved, but well bore restrictions occur
Solution Approach 1:
The system ensures continuous operation by immediately following the seal-setting operation with a milling operation. The mill is positioned to follow the heater, and after the alloy seal is melted and set, the mill automatically engages to remove the seal material, ensuring uninterrupted flow path creation without leaving restrictive seal material in place.
3Temperature
If eutectic alloys melting at 300°C or below are used, then setting temperature can be reduced, but control of melting process becomes more critical
Solution Approach 1:
The patent specifies using eutectic or bismuth-based alloys with melting points of 300°C or below, representing a deliberate parameter change from traditional higher-temperature seal materials. This lower temperature requirement simplifies the heating system design while maintaining effective sealing capability in well bore applications.
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 single trip well repair solutions at economical rates, providing high-integrity seals that can withstand pressure differentials and corrosion, while minimizing well bore restrictions and the need for multiple trips.
Implementation Method 1
a tubular heater with an exothermic chemical reaction heat source
Implementation Method 2
the tubular heater and the tubular mandrel are in thermal communication
Implementation Method 3
The heat from the heater is used to melt the alloy
Implementation Method 4
Mills, milling, fishing, spearing, grappling and drilling techniques are as old as the oil field itself
Data Source
AI summary
The present invention provides a tool assembly system for use in a single trip downhole operation in which an alloy plug/seal is set and then at least partially milled through. The system comprises a tubular chemical heater with a mill that has at least one flow port and a tubular mandrel arranged on the outside of the heater at up-hole and down-holes ends of the heater respectively and whereby the heater is removably retained within the mandrel so that the mill can be subsequently repositioned to work on the mandrel once the alloy plug/seal has been formed. The present invention also provides an associated method of forming an alloy plug/seal and milling it at least partially through in a single trip.