Seismic Sensor Disconnection Detection via Offset Signal Analysis
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Solution Overview
Problem
Existing seismic data acquisition systems face challenges in continuously detecting partial or total disconnections of analog seismic sensors due to mechanical and climatic constraints, leading to poor data quality and false alarms, especially in continuous acquisition modes where regular resistance measurements are impractical.
Innovation Solution
An acquisition device with a pair of input terminals that injects a low current to generate an offset signal, allowing for continuous disconnection detection by analyzing temporal variations of the measured signal, independent of other devices and without interfering with the seismic signal, using digital filtering to separate the offset and seismic signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If regular resistance measurements are performed to detect sensor disconnections, then disconnection detection capability is improved, but continuous acquisition is interrupted and productivity decreases
Solution Approach 1:
The patent implements continuous disconnection detection during seismic acquisition by injecting a low-level test current that operates simultaneously with the acquisition process, eliminating the need to interrupt data collection for detection measurements
Solution Approach 2:
The system uses periodic sampling of the offset signal at predetermined time intervals to monitor resistance changes, enabling continuous detection while maintaining minimal interference with the ongoing acquisition process
2Measurement precision
If high current is injected to generate detectable offset signal, then measurement precision is improved, but interference with seismic signal increases and data quality deteriorates
Solution Approach 1:
The patent optimizes the test current magnitude to a low level that generates a measurable offset signal while remaining below the threshold that would interfere with the seismic signal, balancing detection precision with signal integrity
Solution Approach 2:
The system injects only the minimum necessary current to generate a detectable offset signal, using partial action rather than full-strength measurement currents, thereby achieving sufficient measurement precision without excessive interference
3Reliability
If absolute resistance values are measured to detect disconnections, then detection capability is improved, but false alarms increase due to temperature variations
Solution Approach 1:
The system performs an initial offset measurement to establish a reference value, then compares subsequent measurements against this reference to detect changes, thereby compensating for temperature drift and reducing false alarms
Solution Approach 2:
The system continuously monitors offset signal variations and uses feedback from previous measurements to distinguish between normal temperature-induced changes and actual disconnection events, improving detection reliability
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 continuous disconnection detection during seismic acquisition without impacting data quality, reducing false alarms, and is compatible with autonomous systems by focusing on relative resistance changes rather than absolute values, thus improving the reliability of seismic data acquisition.
Implementation Method 1
means for injecting a low current in the set of at least one analog seismic sensor, in order to generate an offset signal which depends partially on the electrical resistance of the set of at least one analog seismic sensor
Data Source
AI summary
An acquisition device includes a pair of input terminals for connection to an analog seismic sensor generating a seismic signal. The device includes a detector for detecting a disconnection of the sensor, which includes a current source for injecting a low current in the sensor to generate an offset signal which depends on electrical resistance of the sensor and is added to the seismic signal. The offset signal encroaches on only a part of an operating range of the acquisition device. The voltage measured at the input terminals is applied to an analog-digital converter and a filter to obtain a measured value of the offset signal. A processing unit either analyzes a temporal variation of the measured value and triggers an alarm if a determined condition is satisfied, or transmits the measured value to a remote device adapted to analyze the temporal variation.