Guided Wave Attenuation via Polarization Filtering
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Solution Overview
Problem
Existing seismic surveying techniques struggle to filter out guided waves from seismic data, leading to excessive noise that hinders accurate characterization of rock formations and hydrocarbon reservoirs, as these waves do not exhibit distinctive polarization characteristics like interface waves.
Innovation Solution
The method involves scaling raw seismic data from hydrophone and geophone components and applying polarization filtering based on ellipticity ratios or tilt angles within specific velocity constraints to attenuate guided waves, producing attenuated seismic data with reduced noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional polarization filtering is applied to seismic data, then interface waves such as Rayleigh waves and Scholte waves can be filtered out, but guided waves cannot be attenuated because they do not exhibit distinctive elliptical polarization characteristics
Solution Approach 1:
The patent changes the polarization filtering parameters by introducing scaling factors that modify the relationship between hydrophone and geophone components. This creates an artificial elliptical polarization effect for guided waves, enabling them to be filtered alongside interface waves using the same polarization filtering technique.
2Reliability
If no filtering is applied to guided waves, then all seismic signals are preserved, but excessive noise in seismic images prevents accurate characterization of rock formations and hydrocarbon reservoirs
Solution Approach 1:
The patent applies preliminary scaling to the seismic data components before polarization filtering. This preliminary action modifies the data structure to create distinguishable polarization characteristics for guided waves, enabling their subsequent attenuation and improving seismic image reliability.
3Ease of manufacture
If existing filtering techniques are used, then interface waves can be removed, but other types of waves that are sources of noise remain unfiltered
Solution Approach 1:
The patent makes the polarization filtering process universal by enabling it to handle both interface waves and guided waves through the same technique. The scaling mechanism allows a single filtering approach to address multiple types of noisy waves, eliminating the need for separate filtering processes.
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 effectively reduces noise from guided waves in seismic data, enhancing the accuracy of seismic images by isolating the desired signal waves, thereby improving the characterization of rock formations and hydrocarbon reservoirs.
Implementation Method 1
Polarization filtering is typically used to filter interface waves such as Rayleigh waves (in land environments) and Scholte waves (in marine environments) from multicomponent seismic data. Interface waves such as Rayleigh and Scholte waves exhibit a distinctive characteristic—elliptical polarization—that may be exploited to filter these waves from body waves
Implementation Method 2
Interface waves such as Rayleigh and Scholte waves exhibit a distinctive characteristic—elliptical polarization—that may be exploited to filter these waves from body waves
Data Source
AI summary
Systems, methods, and computer-readable media for attenuating guided waves in seismic data using polarization filtering are provided. A raw hydrophone component and raw geophone component of multicomponent seismic data may be scaled using a constant scalar to enhance the ellipticity ratio of guided waves. Polarization filtering based on the ellipticity ratio may be applied within a velocity constraint to the scaled hydrophone and vertical geophone components to attenuate the guided waves. Additionally or alternatively, polarization filtering based on the tilt angle may be applied within a velocity constraint to the raw hydrophone and vertical geophone components to attenuate the guided waves. Polarization filtering may be applied to a raw hydrophone component and raw vertical geophone component of seismic data to attenuate Scholte waves before attenuation of the guided waves.