Magnetic Permeability Sensor Direction Detection for Downhole Counting
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Solution Overview
Problem
Downhole devices in well completions often miscount objects due to lack of directionality in sensors, leading to premature actuation and potential damage or deviation from completion plans, as objects can travel back uphole and be counted incorrectly.
Innovation Solution
A magnetic field sensor disposed between opposing permanent magnets is used to detect the direction of magnetically permeable objects, allowing circuitry to accurately count objects by incrementing or decrementing based on their direction of travel, thereby preventing false triggering of downhole devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single sensor is used to detect objects passing through a wellbore, then device complexity is reduced, but measurement precision deteriorates because the sensor cannot distinguish the direction of object travel
Solution Approach 1:
The patent applies local quality by creating an asymmetric magnetic field configuration where the first and second magnets are positioned at different locations relative to the sensor. This local asymmetry in the magnetic field allows the single sensor to detect directionality - when an object approaches from one direction, it disturbs the magnetic field differently than when approaching from the opposite direction, enabling precise direction detection without requiring multiple sensors
Solution Approach 2:
The invention implements asymmetry through the non-symmetric arrangement of magnets around the sensor. The first magnet is positioned on one side of the sensor while the second magnet is positioned on the opposite side at a different distance or orientation. This asymmetric configuration creates distinct magnetic field patterns for objects traveling in opposite directions, allowing the single sensor to distinguish direction while maintaining device simplicity
2Device complexity
If direction detection is not implemented, then device complexity remains low, but reliability deteriorates due to incorrect object counting and premature device actuation
Solution Approach 1:
The system implements feedback by continuously monitoring the magnetic field disturbances and using the detected direction information to adjust the object count. When an object is detected traveling in the wrong direction (e.g., returning uphole), the system uses this feedback to decrement or ignore the count, preventing premature actuation. This feedback mechanism ensures reliable operation while maintaining a relatively simple counting system
Solution Approach 2:
The patent applies preliminary action by establishing the asymmetric magnetic field configuration before objects are introduced into the wellbore. This pre-configured magnetic field is ready to detect and distinguish object direction from the moment an object enters the detection zone, preventing counting errors before they occur rather than correcting them after the fact
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 accurate counting of objects, preventing premature actuation of downhole devices and maintaining the integrity of well completion plans by accounting for the direction of object travel, thus enhancing the reliability and safety of well operations.
Implementation Method 1
a magnetic field sensor disposed between opposing permanent magnets and configured to detect changes in magnetic permeability in response to passage of one or more magnetically permeable objects
Implementation Method 2
A magnetic field sensor disposed between opposing permanent magnets
Data Source
AI summary
Apparatus, methods, and systems are provided to count one or more magnetically permeable objects that have passed by a magnetic sensor and determine a direction thereof. The apparatus comprises a first permanent magnet; a second permanent magnet; a magnetic field sensor disposed between opposing poles of the first permanent magnet and the second permanent magnet; and a circuit connected to the magnetic field sensor, the circuit configured to count one or more magnetically permeable objects that have passed by the magnetic field sensor, and determine direction of the one or more magnetically permeable objects based on an output of the magnetic field sensor.