Seismic Image Gathers via Separated Migration Assembly Stacking
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Solution Overview
Problem
Conventional seismic imaging methods fail to accurately separate migration and assembly steps, leading to premature summation that obscures imaging deficiencies and limits the capture of velocity-related and other imaging deficiencies, resulting in suboptimal image quality.
Innovation Solution
The method involves fully separating the steps of migration, assembly, and stacking to form 'expanded image-gathers' (EIGs), allowing for post-migration processing and alignment of individual traces in the offset-midpoint domain before summation, enabling the measurement and compensation of imaging deficiencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If migration and assembly are performed simultaneously in conventional seismic imaging, then processing efficiency is improved, but imaging deficiencies cannot be accurately measured and compensated
Solution Approach 1:
The patent segments the conventional simultaneous migration and assembly process into three distinct sequential steps: (1) migration step to relocate seismic energy to correct subsurface positions, (2) assembly step to organize migrated traces into image gathers without summation, and (3) stacking step to perform final summation. This segmentation allows imaging deficiencies to be measured and compensated in the intermediate image gather stage before final stacking, resolving the contradiction between processing efficiency and measurement precision.
2Device complexity
If premature summation is performed in conventional imaging, then computational complexity is reduced, but imaging deficiencies become obscured and cannot be captured
Solution Approach 1:
The patent applies preliminary action by performing migration and assembly operations before the final stacking summation. The image gathers are constructed and analyzed in advance, allowing imaging deficiencies to be identified and compensated before the irreversible summation operation. This preliminary processing preserves information about imaging deficiencies that would otherwise be obscured by premature summation.
3Measurement precision
If conventional image gathers are used, then velocity-related imaging deficiencies can be measured, but other types of imaging deficiencies cannot be addressed
Solution Approach 1:
The patent creates a universal image gather framework that can address multiple types of imaging deficiencies through the same separated migration-assembly-stack processing structure. By maintaining all three processing stages distinctly, the method can handle velocity-related deficiencies, azimuthal variations, dip angle issues, and other imaging problems that conventional single-purpose image gathers cannot address, thereby achieving multi-functionality.
Data Source
AI summary
In the present inventive method, individual traces of seismic data are migrated (41) without any assembling of different midpoints or any summing of different offsets, so that post-migration processing or analysis, e.g. trace alignment, may be applied to the individual migrated traces (42) to compensate for any deficiencies among them, before stack and assembly. Thus, the present invention fully separates the steps of migration (41), assembly (43), and stacking (44), which are combined together in traditional migration. Thus, imaging deficiencies can be measured and addressed in the image space before they are obscured by summation. Afterward, summation can proceed to construct the improved final image (45).