Seismic Visibility Analysis for Prestack Migration
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Solution Overview
Problem
Conventional seismic surveys often struggle to adequately image certain subsurface features, leading to costly and time-consuming solutions such as more sophisticated processing techniques or additional data acquisition, especially in complex structures like sub-salt formations.
Innovation Solution
A computer-implemented seismic migration method and visibility analysis system that identifies optimal seismic source and receiver positions for improved data acquisition and processing, focusing efforts on specific subsurface features by quantitatively measuring source-receiver visibility and selecting high-visibility traces for more advanced migration techniques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If more sophisticated processing techniques are employed to improve subsurface imaging, then imaging quality improves, but processing time and cost increase
Solution Approach 1:
The patent divides the seismic data processing into two segments: first applying conventional migration to all data, then applying sophisticated prestack migration only to selected high-visibility traces identified by visibility analysis. This segmentation allows sophisticated processing to be applied selectively rather than to the entire dataset, improving imaging quality where needed while reducing overall processing time and cost.
Solution Approach 2:
The patent applies different processing qualities to different parts of the data based on local visibility characteristics. High-visibility traces that clearly reveal subsurface features receive conventional processing, while low-visibility traces that benefit most from sophisticated methods are selected for enhanced migration. This local differentiation optimizes the balance between imaging quality and processing resources.
2Measurement precision
If additional data acquisition is performed to improve subsurface imaging, then imaging quality improves, but acquisition cost and time increase
Solution Approach 1:
The patent performs visibility analysis as a preliminary action before deciding on additional data acquisition. By analyzing the visibility of existing traces, the system identifies which subsurface features are already well-imaged and which require additional data. This preliminary assessment prevents unnecessary additional acquisition while targeting specific areas where it would be beneficial, reducing overall acquisition time and cost.
3Reliability
If conventional migration is applied to all seismic traces, then processing completeness is maintained, but processing efficiency decreases
Solution Approach 1:
The patent extracts and separates high-visibility traces from the full seismic dataset using visibility analysis. These selected traces are then processed with sophisticated prestack migration methods, while the remaining traces undergo conventional migration. This extraction approach maintains processing completeness for all data while significantly improving efficiency by applying computationally intensive methods only where necessary.
4Measurement precision
If sophisticated prestack migration is applied to selected traces, then imaging detail improves, but processing complexity increases
Solution Approach 1:
The patent applies sophisticated prestack migration to only a partial subset of traces that are identified as having low visibility and benefiting most from enhanced processing. Rather than applying the complex method to all traces, this partial action approach achieves improved imaging detail for critical features while reducing the overall computational complexity and processing burden.
Data Source
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AI summary
Seismic visibility analysis of selected subsurface structures is employed to determine surface locations offering high visibility of target events. These locations can then be used as a basis for acquiring additional seismic survey data and/or selecting existing traces for re-migration with more sophisticated migration methods. With either usage, the newly migrated data is expected to offer enhanced images of the target event. In some embodiments, the visibility determination includes using a wave equation based propagator to find, for each of multiple simulated shots, a reflection wavefield from the target event in a seismic model; and to calulate, for each of multiple receiver positions, a contribution signal from each reflection wavefield. The visibility determination further includes converting each contribution signal into a source-receiver visibility value. Because data acquisition and/or re-migration is limited to the selected region, the imaging effort for the target event is significantly reduced.