Adaptive Subtraction for Marine Seismic Noise Attenuation
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Solution Overview
Problem
Geophysical survey data is often contaminated with noise, making it challenging to accurately analyze geological structures, particularly in marine environments where signal and noise components frequently overlap, leading to unwanted artifacts during noise reduction processes.
Innovation Solution
An adaptive subtraction technique is employed, which involves noise template adaptation using least-squares filtering and correlation-based masking to better isolate noise components, thereby reducing noise while minimizing signal distortion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional noise reduction techniques are applied to geophysical data, then noise levels are reduced, but signal distortion and unwanted artifacts increase
Solution Approach 1:
The patent segments the geophysical data into signal components and noise components using multiple noise templates that represent different noise sources. By dividing the noise into separate templates (e.g., multiples, ambient noise, instrument noise), the system can selectively remove each noise type while preserving the primary signal through adaptive subtraction of each template from the total data.
Solution Approach 2:
The patent changes parameters of the noise templates through adaptive subtraction, adjusting template amplitudes, phases, and time delays to match the actual noise in the data. This allows dynamic optimization of noise removal while minimizing signal distortion, as the templates are continuously refined to represent only the noise components.
2Measurement precision
If aggressive noise filtering is applied, then signal-to-noise ratio improves, but geological details and signal fidelity are lost
Solution Approach 1:
The patent implements feedback through iterative adaptive subtraction, where the noise templates are continuously refined based on the residual data after each subtraction step. The system monitors the remaining signal and adjusts the templates to avoid removing genuine geological features, creating a feedback loop that optimizes both noise removal and signal preservation.
Solution Approach 2:
The patent uses dynamic noise templates that adapt their parameters based on the local characteristics of the data. Rather than applying static filtering, the system dynamically adjusts template properties (amplitude, phase, time window) to match the varying noise conditions across different time and spatial domains, preserving signal details that static methods would remove.
Data Source
AI summary
Techniques are disclosed relating to reducing noise in geophysical marine survey data. Such techniques may include adapting an initial set of noise templates to recorded seismic data to generate adapted noise templates and estimating a noise component in the recorded seismic data. The estimating may include determining a degree to which noise and signal components are correlated in the recorded seismic data and masking the recorded seismic data proportionally to the degree of correlation. The adapted noise templates may then be further adapted to a difference between the estimate of the noise component and the noise templates themselves. Resultant noise templates may then be applied to denoise the recorded seismic data.