Degradable Firing Pin for Tubing Perforating Safety
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Solution Overview
Problem
Tubing conveyed perforating systems face safety concerns due to potential failure of mechanical firing heads, where the drop bar may not initiate the perforating gun, leading to uninitiated energetic material that can pose risks during retrieval or unintended firing.
Innovation Solution
A firing head with a degradable firing pin that changes geometry or mechanical strength upon exposure to well bore fluids, rendering the system inoperable over time, ensuring safe degradation and preventing accidental perforation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a mechanical firing head is used in a tubing conveyed perforating system, then the system eliminates accidental electrical firing, but the firing head may fail to initiate the perforating gun, leaving uninitiated energetic material that poses safety risks
Solution Approach 1:
The firing pin is designed as a disposable component made of degradable material that is discarded after a single use. After the perforating operation, the firing pin is left in the well bore where it degrades over time, eliminating the need for retrieval operations that could expose personnel to uninitiated energetic material. This disposable approach transfers the safety risk from retrieval operations to the natural degradation process.
Solution Approach 2:
The harmful factor of uninitiated energetic material is converted into a benefit by using the degradation process as a safety mechanism. The firing pin's degradable material naturally degrades over time, rendering the system inoperable and eliminating the risk of unintended firing. This transforms the potential hazard of retained energetic material into a safety feature that automatically neutralizes the risk.
2Reliability
If the firing pin is made of degradable material, then the system automatically becomes inoperable after a predetermined period, but the firing pin must maintain sufficient mechanical strength during operation to initiate the perforating gun
Solution Approach 1:
The firing pin's mechanical properties are made dynamic rather than static. The material transitions from a high-strength state during operation to a degraded state after the predetermined period. This dynamic behavior allows the firing pin to meet both requirements: sufficient strength during operation and automatic inoperability after the degradation period. The material's properties change based on the operational context and time elapsed.
Solution Approach 2:
The mechanical strength parameter of the firing pin changes over time through the degradation process. The degradable material maintains adequate strength during the operational window but progressively loses strength until the system becomes inoperable. This parameter change allows the same component to satisfy both the operational strength requirement and the safety inoperability requirement without additional design complexity.
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 degradable firing pin mechanism ensures the perforating system becomes inoperable within a predetermined period, mitigating safety risks and allowing for controlled retrieval or natural degradation, eliminating the risk of unintended firing.
Implementation Method 1
The firing pin is configured to degrade over a predetermined period of time from an initial state to a degraded state
Data Source
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AI summary
A tubing conveying perforating system with a firing head is provided, and a method for using the same is provided. The firing head (20) includes a firing pin (24) and a percussion initiator (26). The firing pin is configured to degrade over a predetermined period of time from an initial state to a degraded state, and in the degraded state the firing head is inoperable..