Safe Firing Head with Gravity-Actuated Stopper for Deviated Wellbores
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Solution Overview
Problem
Firing heads for downhole tools often initiate detonation trains unintentionally, especially in deviated well orientations, which can lead to unsafe and inefficient well operations.
Innovation Solution
A firing head design featuring a housing with a radially enlarged chamber and a moveable stopper that prevents the pin from contacting the initiator unless a predetermined angular deviation from the vertical position is present, ensuring the tool is in the correct orientation before activation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a firing head is used to initiate detonation in downhole tools, then the tool can be activated to perform well operations, but unintended detonation may occur in vertical or undesired orientations
Solution Approach 1:
The stopper is designed to be movable relative to the pin, allowing it to dynamically change position based on the housing orientation. In vertical orientation, the stopper blocks the pin; in deviated orientation, gravity causes the stopper to move away from the pin, enabling detonation. This dynamic positioning resolves the contradiction by making activation dependent on orientation.
Solution Approach 2:
The system changes the physical state of the stopper position based on the orientation parameter of the housing. By utilizing gravitational force, the stopper's position parameter changes from blocking (vertical) to non-blocking (deviated), thereby controlling detonation safety based on orientation parameters.
2Reliability
If a stopper mechanism is added to prevent unintended detonation, then safety is improved, but the device complexity increases
Solution Approach 1:
The stopper mechanism is designed to be self-actuating through gravity. The housing orientation itself provides the activating force that moves the stopper into or out of the blocking position, eliminating the need for external actuators, sensors, or control systems. This self-service approach adds minimal complexity while achieving reliable orientation-based safety.
Solution Approach 2:
The stopper acts as a simple mechanical intermediary between the housing orientation and the pin-initiator contact. It translates the orientation state into a blocking or non-blocking condition without requiring complex control mechanisms, thereby resolving the contradiction with minimal added 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
This solution ensures that detonation trains are only initiated when the downhole tool is in the desired deviated orientation, enhancing safety and operational efficiency by preventing unintended detonations in vertical or undesired orientations.
Implementation Method 1
The stopper moves out of the groove when the housing has a predetermined minimum angular deviation from the vertical position
Data Source
AI summary
A firing head for selectively activating an initiator of a downhole tool may include a housing, a pin, and a moveable stopper. The housing may have a bore and a radially enlarged chamber formed along the bore. The pin is disposed in the bore and has a circumferential groove formed on an outer surface of the shank. The moveable stopper is disposed in the radially enlarged chamber. The stopper is only partially disposed in the groove when the housing is in a vertical position. The stopper moves out of the groove when the housing has a predetermined minimum angular deviation from the vertical position.