Automated Near Surface Analysis Using Surface-Consistent Refraction
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Solution Overview
Problem
Conventional seismic data processing methods are inadequate for handling large datasets from modern seismic acquisition systems, particularly in near surface analysis, leading to inefficiencies in processing and imaging due to high computational demands and sensitivity to noise and surface effects.
Innovation Solution
A computer-implemented method for forming near surface corrections using surface-consistent refraction analysis, which involves sorting first break datasets into offset bins, removing anomalous arrival times, and applying field static and refraction residual static corrections to seismic traces, enabling automated and efficient near surface analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If full-waveform inversion methods are used for high resolution velocity analysis, then measurement precision is improved, but device complexity and computational power requirements increase dramatically
Solution Approach 1:
The patent segments the complex full-waveform inversion problem into two distinct phases: a first phase using refraction statics for long-wavelength corrections, and a second phase using reflection statics for short-wavelength corrections. This segmentation allows each phase to be optimized independently, reducing overall computational complexity while maintaining high precision velocity analysis.
Solution Approach 2:
The patent performs preliminary refraction statics correction before conducting the main reflection statics analysis. By pre-correcting long-wavelength errors using refraction data, the subsequent reflection-based velocity analysis starts from a better initial state, reducing iterations needed and lowering computational burden.
2Ease of operation
If conventional interactive processing methods are used for near surface analysis, then ease of operation is maintained, but productivity decreases due to time-consuming manual intervention
Solution Approach 1:
The patent implements automated first break picking algorithms that self-correct anomalies using statistical methods and surface-consistent principles. The system automatically identifies and corrects picking errors without requiring manual analyst intervention, enabling the processing system to serve itself and dramatically increasing productivity.
Solution Approach 2:
The patent incorporates feedback mechanisms where the system continuously evaluates picked first breaks, identifies anomalies through statistical analysis, and automatically re-picks or corrects erroneous picks. This closed-loop feedback system maintains high accuracy while eliminating manual intervention.
3Reliability
If refraction statics calculation is performed using traditional methods, then reliability of near surface correction is improved, but loss of time increases due to iterative optimization requirements
Solution Approach 1:
The patent changes the optimization parameter from traditional travel-time residuals to surface-consistent parameters (source terms, receiver terms, and elevation terms). This parameter transformation linearizes the inverse problem, allowing direct solution without iterative optimization, thereby maintaining reliability while dramatically reducing processing time.
Solution Approach 2:
The patent replaces the mechanical iterative optimization process with a direct linear algebraic solution. By formulating refraction statics calculation as a linear system of equations based on surface-consistent principles, the method eliminates the need for time-consuming iterative loops while preserving correction accuracy.
Data Source
AI summary
A surface-consistent refraction analysis automatically derives near surface corrections during seismic data processing. Residual time lags are evaluated in multiple CMP-offset-azimuth bins by similarity analysis with a pilot trace where a correlation window is centered at the refracted arrival. The similarity analysis may take the form of computerized cross-correlation, or other criteria such as semblance. The residuals are then used to build a system of linear equations that is simultaneously inverted for surface-consistent shot and receiver time shift corrections plus a possible subsurface residual term. The refraction analysis steps are completely automated and require a fraction of the time needed for conventional near surface analysis.