Marine Seismic Source Motion Correction via Frequency-Space Domain Inversion
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Solution Overview
Problem
Current marine seismic surveying techniques using moving vibrational sources face challenges in correcting adverse Doppler-related effects, which result in unsuitable seismic data for imaging due to phase dispersions and distortions, especially when traditional processing methods fail to account for variations in vibrational source signatures and environmental conditions.
Innovation Solution
The implementation of generalized expressions for modeling seismic data in the frequency-space domain, allowing for source motion correction, receiver-side deghosting, and designaturing without restrictions on vibrational source signature variations, using frequency-space domain inversion instead of traditional frequency-wavenumber domain division methods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional frequency-wavenumber domain division methods are used for processing seismic data from moving vibrational sources, then processing simplicity is maintained, but phase dispersions and Doppler-related distortions remain uncorrected resulting in unsuitable imaging data
Solution Approach 1:
The patent transforms the processing domain from frequency-wavenumber to frequency-space domain, changing the mathematical parameters used in the processing equations. This allows for proper correction of Doppler effects and phase dispersions while maintaining a systematic processing approach through generalized expressions that account for source motion and environmental variations
Solution Approach 2:
The patent inverts the traditional processing approach by using frequency-space domain inversion instead of frequency-wavenumber domain division. This inversion method properly accounts for the moving source effects and enables correct separation of primary reflections from multiples and noise, thereby improving imaging quality
2Measurement precision
If generalized expressions accounting for source motion and environmental variations are implemented, then correction accuracy is improved, but computational complexity increases
Solution Approach 1:
The patent changes the domain parameters from frequency-wavenumber to frequency-space, enabling more accurate modeling of source motion effects. The generalized expressions incorporate velocity variations, water depth changes, and source signature variations, achieving superior correction accuracy despite increased computational requirements
3Object-affected harmful factors
If marine vibrators are used as seismic sources, then environmental impact is reduced, but Doppler-related effects and phase dispersions are introduced requiring complex correction
Solution Approach 1:
The patent converts the harmful Doppler effects and phase dispersions generated by moving vibrators into correctable signals by using generalized frequency-space domain expressions. These expressions explicitly model the source motion effects, allowing the processing system to remove the artifacts while retaining the beneficial environmental impact advantages of using vibrators over air guns
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 generates high-resolution images of subterranean formations by correcting Doppler effects and removing source-related distortions, improving the accuracy of seismic data processing and reducing environmental impact.
Implementation Method 1
A seismic source may be an impulsive source, such as an array of air guns, that are activated to produce acoustic energy with an impulsive signature. Alternatively, a seismic source may be a marine vibrator that emits acoustic energy with a substantially constant signature over a longer time period. The acoustic energy generated by a seismic source spreads out in all directions.
Implementation Method 2
Current marine seismic surveying techniques using moving vibrational sources face challenges in correcting adverse Doppler-related effects, which result in unsuitable seismic data for imaging due to phase dispersions and distortions
Implementation Method 3
At each interface between different types of liquid, rock and sediment, a portion of the sound wave is refracted, a portion is transmitted, and another portion is reflected into the body of water to propagate as a reflected wavefield toward the water surface.
Data Source
AI summary
Processes and systems are described for generating an image of a subterranean formation from seismic data recorded during a marine survey that employed a moving vibrational source. Processes and systems compute an up-going pressure wavefield from pressure data and vertical velocity data recorded in the marine survey. A direct incident downgoing vertical velocity wavefield that includes Doppler effects created by the moving vibrational source and characterizes a source wavefield and source ghost of the moving vibrational source is computed and deconvolved from the upgoing pressure wavefield to generate a subsurface reflectivity wavefield. The subsurface reflectivity wavefield is effectively free of contamination from the source wavefield, the source ghost, and the Doppler related effects. Processes and systems generate an image of the subterranean formation based on the subsurface reflectivity wavefield, thereby enhancing resolution of the image by attenuating the source-motion effects, source signature, and source ghost of the moving vibration source.