Wave-field Separation for Non-Flat Seismic Recorders
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Solution Overview
Problem
Current seismic data processing techniques struggle to accurately separate up-going and down-going wave fields due to the assumption of a planar recording surface, which is not valid for non-flat acquisition surfaces such as the ocean bottom or varying depths in land seismic data, leading to spurious effects in the final image.
Innovation Solution
A method and system that receive seismic data recorded on a non-flat datum, establish a mathematical relation between transformed seismic data and up-going and down-going wave fields on a planar datum, and solve this relation using an inversion procedure to obtain the wave fields, accounting for the non-planar surface by using wave-field extrapolation terms and specialized computer software.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional wave-field separation techniques are used assuming a planar recording surface, then the processing is simple and computationally efficient, but the separation accuracy deteriorates when the actual recording surface is non-flat
Solution Approach 1:
The patent transforms the seismic data from the time-space domain to the frequency-wavenumber domain, changing the parameter representation to enable accurate wave-field separation on non-flat datums. This domain transformation allows the application of plane datum separation techniques to corrected data, resolving the contradiction between accuracy and complexity.
Solution Approach 2:
The patent introduces an intermediate step of datum correction that transforms non-flat datum seismic data into an equivalent plane datum representation. This intermediary transformation enables the use of simpler plane datum separation algorithms while maintaining accuracy for the original non-flat surface.
2Adaptability or versatility
If seismic recorders are deployed on non-flat surfaces to adapt to complex terrain or ocean bottom, then the adaptability improves, but the wave-field separation accuracy deteriorates due to violation of planar surface assumption
Solution Approach 1:
The patent applies parameter changes by transforming the spatial domain representation of seismic data to account for the non-flat datum geometry. Through coordinate transformations and wave-field extrapolation, the method adapts the separation algorithm to handle arbitrary datum surfaces while maintaining separation accuracy.
Solution Approach 2:
The patent moves the problem from the spatial domain to the frequency-wavenumber domain, adding a dimensional transformation that enables the handling of non-flat surfaces. This domain change allows the application of plane datum techniques to corrected data through proper wave-field extrapolation.
Data Source
AI summary
Apparatus, computer instructions and method for separating up-going and down-going wave fields (U, D) from seismic data recorded within or beneath a body of water, or in general below the surface of the earth. The method includes a step of receiving seismic data (Po, Zo) recorded in the time-space domain with seismic recorders distributed on a first datum, wherein the first datum is non-flat; a step of establishing a mathematical relation between transformed seismic data (P, Z) and the up-going and down-going wave fields (U, D) on a second planar datum; and a step of solving with an inversion procedure, run on a processor, the mathematical relation to obtain the up-going and down-going wave fields (U, D) for the second datum. The second datum is different from the first datum.