Propellant Back Off Tool for Stuck Tubular Recovery
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Solution Overview
Problem
Conventional well tubular recovery methods using explosive devices are regulated, costly, and pose handling risks, while existing non-explosive solutions lack the necessary concussive force to effectively loosen stuck tubular connections.
Innovation Solution
A pipe recovery system employing a propellant assembly with a solid propellant, such as potassium perchlorate mixed with a binding agent, which provides a controlled energy release to uncouple stuck tubular connections, utilizing a propellant chamber, expansion chamber, and acceleration mass to generate a shockwave for loosening.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If explosive devices (detonating cord) are used to loosen stuck tubular connections, then sufficient concussive force is achieved, but regulatory complexity and handling risks increase
Solution Approach 1:
The patent changes the fundamental parameter of the energy release mechanism from explosive detonation to propellant combustion. This substitution maintains the necessary concussive force for loosening stuck connections while eliminating the regulatory and handling risks associated with explosive devices. The propellant assembly generates equivalent mechanical energy through controlled combustion rather than chemical explosion.
Solution Approach 2:
The patent employs a disposable propellant assembly that can be easily deployed and discarded after single use. This approach replaces complex, regulated explosive devices with a simpler, less restricted propellant system that achieves the same functional outcome without requiring special permits or safety protocols for storage and transport.
2Reliability
If conventional explosive initiators are used, then reliable ignition is achieved, but cost and regulatory burden increase
Solution Approach 1:
The patent extracts the initiator component from the overall system by eliminating the need for separate explosive initiators. The propellant assembly is designed to be self-igniting or ignitable by simple means, removing the complex initiator subsystem and its associated regulatory requirements while maintaining reliable ignition capability.
3Object-affected harmful factors
If propellant is used instead of explosive, then regulatory and handling risks are reduced, but energy release duration increases
Solution Approach 1:
The patent designs the propellant combustion process to occur in controlled stages or pulses, creating a periodic action pattern. This allows the energy release to be extended over a longer duration while maintaining sufficient peak forces to loosen stuck connections, thereby reducing handling risks without compromising effectiveness.
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 system effectively loosens stuck tubular connections with reduced regulatory and handling risks, providing a cost-effective alternative to explosive devices by delivering energy over a longer period, ensuring efficient recovery of well tubulars without breaking connections above the collapse.
Implementation Method 1
igniting the propellant, causing the acceleration mass to accelerate
Implementation Method 2
causing the acceleration mass to accelerate along the longitudinal axis of the acceleration chamber and to strike the first end of the transfer piston
Data Source
AI summary
An apparatus includes a propellant chamber, an expansion chamber, an exit chamber comprising a port providing fluid communication outside the apparatus, and a longitudinal acceleration chamber. The longitudinal acceleration chamber includes a first end in fluid communication with the propellant chamber, a second end in fluid communication with the expansion chamber, and a longitudinal axis between the first end and the second end. An acceleration mass is slidably contained in the acceleration chamber. The acceleration chamber includes a propellant side between the propellant chamber and the acceleration mass, and a target side between the acceleration mass and the expansion chamber. A transfer piston is slidably positioned between the expansion chamber and the exit chamber. The transfer piston includes a first end projecting into the expansion chamber and aligned with the longitudinal axis of the acceleration chamber, and a second end projecting into the exit chamber.