Correlation-Based Low-Order Harmonic Attenuation in Vibroseis Data
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Solution Overview
Problem
Existing seismic data acquisition systems using vibratory sources like vibroseis trucks introduce low-order harmonic noise due to non-linearities, which contaminates the seismic data and hinders accurate imaging and extraction operations.
Innovation Solution
A vibroseis tool that correlates and decorrelates harmonic signals with recorded seismic data to remove low-order harmonic noise by autocorrelating and decorrelating signals based on matching times, subtracting noise once the magnitude exceeds a threshold, thereby enhancing the frequency range and accuracy of seismic data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If vibratory sources are used to transmit seismic energy, then direct control over the seismic signal is achieved, but low-order harmonic noise is introduced due to non-linearities
Solution Approach 1:
The patent extracts and removes the harmful low-order harmonic noise components from the seismic signal through correlation-based attenuation methods, separating the useful seismic data from the noise generated by vibratory source non-linearities
Solution Approach 2:
The patent uses the known characteristics of the ground sweep signal to identify and exploit the harmonic noise patterns, converting the harmful non-linear effects into detectable and removable artifacts through correlation with the expected signal structure
2Object-generated harmful factors
If correlation-based attenuation is applied to remove harmonic noise, then noise reduction is achieved, but processing complexity increases
Solution Approach 1:
The patent replaces complex mechanical noise filtering systems with computational correlation-based methods, using digital signal processing to achieve noise attenuation through mathematical operations rather than physical filtering mechanisms
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
The vibroseis tool effectively removes low-order harmonic noise, revealing masked high-frequency information and enabling more accurate seismic data for precise oil recovery operations, including reservoir characterization and equipment deployment.
Implementation Method 1
attenuating a given harmonic signal by correlating the given harmonic signal of the ground sweep with the recorded seismic data
Implementation Method 2
autocorrelating the given harmonic signal of the ground sweep
Implementation Method 3
decorrelating the given harmonic signal of the ground sweep with the recorded seismic data based on the matching time to generate a decorrelated signal
Data Source
AI summary
A method for attenuating low order harmonic noise in recorded seismic data that includes receiving the recorded seismic data in response to vibroseis operations injecting a ground sweep into the Earth. The method further includes attenuating a fundamental order harmonic signal and a given harmonic signal of the ground sweep. Attenuating the given harmonic signal includes correlating the given harmonic signal of the ground sweep with the recorded seismic data and autocorrelating the given harmonic signal of the ground sweep. Attenuating the given harmonic signal further includes finding a matching time between the autocorrelated given harmonic signal and the given harmonic signal correlated with the recorded seismic data. Moreover, attenuating the given harmonic signal includes decorrelating the given harmonic signal of the ground sweep with the recorded seismic data based on the matching time to generate a decorrelated signal and subtracting the decorrelated signal from the recorded seismic data.