Streamer Roll Compensation Using Magnetometer Orientation
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Solution Overview
Problem
In marine geophysical surveying, fixed-mount geophysical sensors face challenges in accurately determining orientation, especially the horizontal component, due to roll effects, and existing methods using DC-coupled accelerometers are contaminated by translational acceleration noise.
Innovation Solution
The use of a method and apparatus that includes a streamer with geophysical sensors and orientation sensor packages, each comprising a magnetometer, to determine and compensate for instantaneous roll angles, reducing noise contamination and improving data accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If DC-coupled accelerometers are used to determine orientation, then roll angle measurement is provided, but translational acceleration noise contaminates the measurement
Solution Approach 1:
A magnetometer is introduced as an intermediary sensor to measure the Earth's magnetic field and determine roll angle independently of translational acceleration. The magnetometer serves as a mediator that provides orientation information without being affected by the harmful translational acceleration noise that contaminates accelerometer measurements.
Solution Approach 2:
The patent replaces the mechanical accelerometer-based orientation sensing system with a magnetic field-based magnetometer system. This substitution eliminates the sensitivity to mechanical translational acceleration while maintaining the ability to determine roll angle through magnetic field orientation measurements.
2Device complexity
If fixed-mount sensors are used in streamers, then device complexity is reduced, but accurate determination of horizontal orientation component becomes difficult due to roll effects
Solution Approach 1:
The patent changes the measurement parameter from mechanical acceleration (which is affected by roll) to magnetic field orientation (which provides direct horizontal reference). By measuring the orientation of the magnetic field vector rather than relying on acceleration components, the system achieves accurate horizontal orientation determination while maintaining fixed-mount simplicity.
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 approach provides accurate roll compensation of vectorised motion data, reducing noise interference and enhancing the reliability of geophysical data collected during marine seismic surveys.
Implementation Method 1
each comprising a magnetometer, to determine and compensate for instantaneous roll angles
Data Source
AI summary
Included are methods and apparatus for marine geophysical surveying. One embodiment of the presently-disclosed solution relates to a method for instantaneous roll compensation of vectorised motion data originating from a fixed-mount geophysical sensor during a marine seismic survey. A streamer is towed behind a survey vessel in a body of water. The streamer includes a plurality of geophysical sensors and a plurality of orientation sensor packages. Vectorised geophysical data is acquired using the plurality of geophysical sensors, while orientation data is acquired by the plurality of orientation sensor packages. The orientation data is used to determine an instantaneous roll angle of the streamer at different positions on the streamer. The vectorised geophysical data is adjusted to compensate for the instantaneous roll angle of the streamer at different positions on the streamer. Other embodiments and features are also disclosed.