Wellbore Tool Arming Layout for Ballistic Safety
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Solution Overview
Problem
The assembly and deployment of wellbore tool strings are expensive and time-intensive, with safety risks due to premature firing or misfiring of perforating guns, and current regulations limit pre-assembly to ensure safety, necessitating on-site assembly of initiators/detonators, increasing operational costs and risks.
Innovation Solution
A ballistically-safe wellbore tool design with an initiator and explosive device configuration switchable between safe and operable positions, using a bias member to maintain a safe distance during transport and a coupling force to enable arming upon assembly, adhering to the 'electric before ballistic arming' (EBBA) standard.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the initiator is installed in the perforating gun before shipment, then assembly time and costs are reduced, but safety risks increase due to potential premature firing
Solution Approach 1:
The system transitions from a static unsafe state to a dynamic safe state through the use of a bias member that actively maintains separation between the initiator and explosive device during transport. The configuration is dynamic, allowing the components to be separated during shipping and automatically brought together when needed at the wellsite.
Solution Approach 2:
The perforating gun is divided into separate modules: the explosive device remains in the gun while the initiator is housed in a separate initiator receptacle. This segmentation allows the tool to be shipped in a safe, disassembled state and assembled at the wellsite, reducing transport risks while enabling pre-assembly benefits.
2Reliability
If the initiator is kept at a safe distance from the explosive device during transport, then safety is improved, but additional on-site assembly work is required
Solution Approach 1:
The bias member automatically maintains the safe distance between the initiator and explosive device during transport without requiring manual intervention. The system serves itself by using the bias member to enforce safety constraints, eliminating the need for complex manual assembly procedures at the wellsite.
Solution Approach 2:
The bias member acts as an intermediary mechanism between the initiator and explosive device, automatically managing their relative positions. This intermediary component handles the safety-critical function of maintaining separation, simplifying the overall assembly operation at the wellsite.
3Reliability
If government regulations limit pre-assembly of tool strings, then safety is ensured, but assembly time and costs increase
Solution Approach 1:
The explosive device and initiator are pre-positioned in their respective locations within the tool string during manufacturing, with the bias member pre-installed to maintain separation. This preliminary action allows the components to be ready for deployment while maintaining safety during transport, complying with regulations while improving efficiency.
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 safe pre-assembly and transport of wellbore tools, reducing assembly time and costs while ensuring personnel safety by allowing electrical arming before ballistic arming, thus minimizing on-site work and risks.
Implementation Method 1
a bias member configured to bias the initiator and the explosive device to the first configuration via a biasing force
Implementation Method 2
providing a coupling force to act against the biasing force such that the initiator and the explosive device transition from the first configuration to the second configuration
Data Source
AI summary
A ballistically-safe wellbore tool may include an explosive device, an initiator including an initiating charge, and a bias member. A relative configuration of the explosive device and the initiator may be switchable between a first configuration, in which the initiating charge is at a ballistically safe distance from the explosive device, and a second configuration, in which the initiating charge is within a ballistically operable distance from the explosive device. The bias member is configured to bias the explosive device and the initiator to the first configuration.