Downhole Tool Movement Detection via Magnetic Field Interaction
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Solution Overview
Problem
Conventional measurement techniques, such as accelerometers, are unable to detect slow movement of seal assemblies in wellbores, which can indicate impending failure due to long service life and high pressures, and are ineffective below a certain movement threshold.
Innovation Solution
An apparatus and method utilizing a primary magnetic field generator and an induced magnetic field sensor coupled to downhole tools to detect movement by sensing changes in the induced magnetic field, allowing for the detection of slow movements that conventional methods miss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional measurement techniques such as accelerometers are used to detect movement, then the device complexity is reduced and ease of operation is improved, but the measurement precision deteriorates because they cannot detect slow movement below a certain threshold
Solution Approach 1:
The patent replaces mechanical accelerometers with a magnetic field-based measurement system. A primary magnetic field generator creates a magnetic field that interacts with a secondary magnetic field generator on the casing, and a sensor detects changes in this magnetic field to measure movement. This substitution enables detection of slow movements below the threshold of conventional mechanical accelerometers.
Solution Approach 2:
The patent changes the measurement parameter from mechanical acceleration to magnetic field interaction. By using a primary magnetic field generator and sensor to detect changes in magnetic field strength or configuration caused by relative movement, the system achieves higher measurement precision for slow movements while maintaining acceptable device complexity.
2Reliability
If seal assemblies are designed for long service life under high pressures, then the reliability is improved, but the difficulty of detecting and measuring deteriorates because movement becomes too slow to detect with conventional techniques
Solution Approach 1:
The patent replaces mechanical acceleration-based detection with a magnetic field-based detection system. The primary magnetic field generator and sensor configuration enables detection of extremely slow movements that occur during long service life, solving the detection difficulty while maintaining the reliability improvements from long-service-life design.
Solution Approach 2:
The patent introduces a magnetic field as an intermediary between the seal assembly and the detection system. The primary magnetic field generator creates a field that serves as a mediator, allowing the sensor to detect subtle positional changes and slow movements of the seal assembly without direct mechanical contact or complex mechanical sensors.
3Measurement precision
If a primary magnetic field generator and induced magnetic field sensor are used to detect slow movement, then the measurement precision is improved, but the device complexity increases
Solution Approach 1:
The magnetic field-based measurement system serves multiple functions: it detects slow movements, measures positional changes, and can potentially detect both axial and radial movements depending on configuration. This multi-functionality justifies the increased device complexity by providing comprehensive measurement capabilities that conventional single-purpose accelerometers cannot achieve.
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 the detection of movement between downhole components, including seal assemblies and well casings, even below the threshold detectable by accelerometers, providing early warning of potential failures and monitoring of positional changes.
Implementation Method 1
A second downhole component is positioned relative to the first downhole component such that the primary magnetic field is imposed on the second downhole component which generates an induced magnetic field that interacts with the primary magnetic field
Data Source
AI summary
An apparatus for detecting movement downhole includes a first downhole component (106) having a sensor (114) coupled thereto and a second downhole component (102) positioned relative to the first downhole component (106). The sensor (114) generates a primary magnetic field that is imposed on the second downhole component (102) thereby generating an induced magnetic field that interacts with the primary magnetic field. Movement of the first downhole component (106) relative to the second downhole component (102) is detected by the sensor (114) by sensing a change in the induced magnetic field.