Downhole Initiator Misalignment Mechanism for Perforating Guns

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Solution Overview

Problem

Existing downhole perforating systems face challenges in preventing inadvertent firing of perforating charges due to electrostatic discharge (ESD) or radio frequency (RF) signals, which can trigger unintended explosive events.

Innovation Solution

Incorporating a ballistic train with an actuator that misaligns components to disarm the initiator, ensuring that only intentional fire commands align the explosives for detonation, thereby preventing unintended firing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional initiator is used without misalignment mechanism, then the device complexity is reduced, but the reliability against inadvertent firing is worsened

Engineering Contradiction:

Improveprevention of inadvertent firingVSAvoidinitiator structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The initiator uses a movable component (actuator) that dynamically changes the alignment state of the ballistic train components between aligned (firing) and misaligned (safe) positions. This dynamic mechanism allows the initiator to transition between armed and disarmed states, preventing inadvertent firing while maintaining operational capability.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The initiator is divided into separate functional components: the ballistic train, the actuator, and the alignment mechanism. This segmentation allows independent control of the firing sequence and safety functions, enabling the misalignment feature to be added without completely redesigning the entire initiator system.

Inventive Principle:

Principle #1Segmentation

2Reliability

If components of the ballistic train are misaligned to prevent inadvertent firing, then the reliability is improved, but the device complexity increases

Engineering Contradiction:

Improvesafety barrier against ESD and RF signalsVSAvoidballistic train configuration

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The initiator is configured in a predetermined misaligned (safe) state before deployment. This preliminary safety configuration ensures that the ballistic train components are already positioned to prevent inadvertent firing upon arrival at the wellsite, eliminating the need for additional safety checks or activation steps.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The actuator serves as an intermediary component that controls the relative positioning of the ballistic train elements. By introducing this intermediate mechanism, the system can safely transition between aligned and misaligned states without direct manual intervention, maintaining reliability while managing complexity.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Object-affected harmful factors

If an actuator mechanism is added to misalign ballistic train components, then the protection against harmful factors is improved, but the ease of manufacture is worsened

Engineering Contradiction:

Improveprotection against ESD and RF signalsVSAvoidinitiator assembly

Core Design Contradiction:

Object-affected harmful factorsVSEase of manufacture

Solution Approach 1:

The actuator mechanism replaces complex electrical or electronic safety systems with a purely mechanical misalignment approach. This substitution simplifies the manufacturing process by eliminating the need for sophisticated electronic controls, sensors, or software, while still providing robust protection against electrostatic discharge and RF signals.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The actuator and misalignment mechanism are designed as simple, potentially disposable components that can be easily manufactured and integrated into the initiator. This approach prioritizes safety functionality over long-term reusability, allowing for cost-effective production of safety-critical components.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Data Source

PatentUS8056632B2Downhole initiator for an explosive end device

Publication Date: 2011.11.15 SCHLUMBERGER TECH CORP

AI summary

A perforating gun that is usable with a well includes at least one perforating charge and a initiator. The initiator includes an explosive ballistic train to the perforating charge(s). The initiator is adapted to physically misalign components of the ballistic train to prevent inadvertent firing of the perforating charge(s) and physically realign the components to arm the ballistic train.