Wavefield Extrapolation for Dual-Sensor Seismic Streamers
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Solution Overview
Problem
Conventional methods for wavefield extrapolation in dual-sensor marine seismic streamer data are compromised by vertical depth variation and horizontal spatial aliasing, leading to inaccurate results when receiver stations are not at the same depth or when recording geometry causes spatial aliasing.
Innovation Solution
A method that calculates time-dependent vertical arrival angles and corrects pressure and particle velocity signals to extrapolate up-going and down-going wavefields at a single receiver station, accounting for non-vertical arrivals and spatial aliasing by using time delays based on arrival angles, allowing for accurate wavefield extrapolation across varying receiver depths and spatial positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional wavefield extrapolation methods are used with receivers at varying depths, then the method is simpler to implement, but the accuracy of wavefield extrapolation deteriorates due to vertical depth variation and horizontal spatial aliasing
Solution Approach 1:
The patent applies parameter changes by introducing time-dependent arrival angles and depth-varying parameters into the wavefield extrapolation process. The method transforms the conventional approach by incorporating depth variation parameters and spatial aliasing correction factors, allowing accurate extrapolation despite receivers being at different depths. This resolves the contradiction by changing the mathematical parameters of the extrapolation method to account for vertical depth variation and horizontal spatial aliasing, thereby maintaining accuracy without requiring complex hardware modifications.
2Reliability
If receivers are positioned at different vertical depths to improve spatial sampling, then spatial aliasing is reduced, but the complexity of wavefield extrapolation increases due to depth variation
Solution Approach 1:
The patent applies dynamics by making the wavefield extrapolation method adaptive to varying receiver depths. Instead of using fixed-depth assumptions, the method dynamically adjusts the extrapolation parameters based on the actual depth of each receiver. The time-dependent arrival angles and depth-varying correction factors allow the system to handle dynamic depth variations, resolving the contradiction by enabling accurate extrapolation for receivers at different depths without requiring a completely complex new system.
Solution Approach 2:
The patent changes the parameters of the wavefield extrapolation method to incorporate depth variation information. By introducing depth-dependent parameters and time-varying arrival angles, the method can process data from receivers at different vertical positions. This parameter transformation allows the system to maintain reliability with improved spatial sampling while managing the complexity through a systematic mathematical framework.
3Ease of operation
If conventional extrapolation methods are used with non-vertical wave arrivals, then the processing is simpler, but the accuracy deteriorates due to spatial aliasing effects
Solution Approach 1:
The patent applies parameter changes by transforming the conventional extrapolation equations to include time-dependent arrival angles. The method introduces angular parameters that vary with time to account for non-vertical wave arrivals. By incorporating these angle-dependent parameters into the extrapolation process, the method maintains simplicity in operation while significantly improving accuracy for oblique arrivals, resolving the contradiction between processing simplicity and extrapolation accuracy.
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 method provides accurate wavefield extrapolation, overcoming spatial aliasing and depth variation issues, ensuring reliable seismic data processing without requiring modifications to the acquisition geometry, thus improving the accuracy of seismic data interpretation.
Implementation Method 1
a pressure sensor and a vertical particle velocity sensor collocated at a single station in a dual-sensor marine seismic streamer
Implementation Method 2
calculating time-dependent arrival angles and correcting pressure and particle velocity signals to extrapolate up-going and down-going wavefields
Data Source
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AI summary
A time-dependent arrival angle is determined at a single receiver station in a towed streamer. Up-going and down-going pressure wavefields are calculated from pressure and vertical particle velocity wavefields measured at the receiver station. Extrapolated up-going and down-going pressure wavefields are generated from the up-going and down-going pressure wavefields displaced by a time delay based upon the time-dependent arrival angle.