Geophone Noise Attenuation via Multi-Dimensional Decomposition
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Solution Overview
Problem
Current methods for processing seismic data, particularly in deep water, face challenges in separating meaningful geophone data from noise, especially V(z) noise, which degrades wavefield separation and imaging quality due to its coherent and amplitude-rich characteristics that are not present on hydrophones.
Innovation Solution
The proposed method involves a 3-D time-slowness (tau-P) transform of dual sensor data, followed by frequency band decomposition, envelope determination, envelope ratio calculation, and scaling of geophone data to align with hydrophone data, and subsequent inverse transformation to enhance wavefield separation and noise removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If dual sensor (hydrophone and geophone) data is used to enhance wavefield separation, then imaging quality should improve, but geophone noise (V(z) noise) degrades the separation and imaging quality
Solution Approach 1:
The patent segments the seismic data into separate hydrophone and geophone components, processes them independently through the tau-P transform and frequency band decomposition, and then recombines them using envelope ratio scaling. This segmentation allows the harmful geophone noise to be identified and separated from the useful signal, enabling selective retention of signal while removing noise.
Solution Approach 2:
The patent uses the hydrophone data as an intermediary reference to correct and scale the geophone data. By computing the envelope ratio of hydrophone to geophone data in the frequency domain, the hydrophone serves as a mediator that provides a clean reference signal to eliminate geophone-specific noise while preserving the useful seismic signal.
2Measurement precision
If geophone data is processed to remove noise, then signal quality improves, but the complexity of processing increases
Solution Approach 1:
The patent transforms the seismic data from the time-domain into the tau-P domain (time-slope domain) using the tau-P transform. This dimensional change allows frequency band decomposition and envelope ratio calculation to be performed in a transformed space where noise and signal are better separated, simplifying the overall processing by leveraging the properties of the transformed domain.
Solution Approach 2:
The patent changes the processing parameters by decomposing the data into frequency bands and computing envelope ratios in the frequency domain rather than processing the entire signal as a whole. This parameter change allows selective scaling of different frequency components, improving signal quality while maintaining processing efficiency through automated envelope ratio calculation.
Data Source
AI summary
Methods and apparatus for processing dual sensor (e.g., hydrophone and vertical geophone) data that includes intrinsic removal of noise as well as enhancing the wavefield separation are provided. The methods disclosed herein are based on a decomposition of data simultaneously into dip and frequency while retaining temporal locality. The noise removed may be mainly coherent geophone noise from the vertical geophone, also known as V(z) noise.