Adaptive Surface Grid Refinement for Seismic Depth Migration
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Solution Overview
Problem
Kirchhoff depth migration in seismic imaging involves extensive computational and storage overhead due to traveltime interpolation errors, especially in areas with complex topography and subsurface heterogeneity.
Innovation Solution
Adaptive refinement of grid cell sizes in the surface grid to locally adjust traveltime interpolation errors within a predetermined threshold, ensuring accuracy by subdividing grid cells where errors exceed the threshold.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If Kirchhoff depth migration is used with fine surface grid to ensure interpolation accuracy, then measurement precision is improved, but productivity deteriorates due to extensive computations and storage overhead
Solution Approach 1:
The surface grid is adaptively subdivided into smaller grid cells only in regions where traveltime interpolation errors exceed the threshold, rather than uniformly refining the entire grid. This selective segmentation reduces the total number of grid cells and associated computations while maintaining accuracy where needed.
Solution Approach 2:
The method applies different grid cell sizes to different regions of the surface based on local error characteristics. Areas with complex topography or large interpolation errors receive finer grid resolution, while homogeneous regions use coarser resolution, optimizing the balance between accuracy and computational efficiency.
2Manufacturing precision
If Kirchhoff depth migration is used with fine surface grid to ensure interpolation accuracy, then manufacturing precision is improved, but device complexity worsens due to storage overhead
Solution Approach 1:
The adaptive grid subdivision creates a non-uniform grid structure where only necessary regions are refined. This segmentation reduces the total number of grid cells and associated traveltime calculations that must be stored, thereby reducing storage overhead while maintaining precision where required.
Solution Approach 2:
By applying fine grid resolution only locally where interpolation errors are problematic rather than uniformly across the entire surface, the method reduces the total data volume that must be stored while preserving manufacturing precision in critical areas.
3Measurement precision
If uniform fine grid is used across the entire surface, then measurement precision is improved, but productivity deteriorates due to unnecessary computations in homogeneous regions
Solution Approach 1:
The method evaluates interpolation errors locally at each grid cell and applies refinement only where needed. Homogeneous regions with acceptable error margins use coarser grid resolution, eliminating unnecessary computations while maintaining measurement precision in regions where it is actually required.
Solution Approach 2:
Rather than applying full grid refinement uniformly across the entire surface, the method applies partial refinement only to specific regions where error thresholds are exceeded. This partial action eliminates wasteful computations in homogeneous regions while maintaining sufficient precision where geological complexity demands it.
Data Source
AI summary
Example methods and systems for seismic depth migration are disclosed. One example method includes obtaining a surface grid of a region for seismic imaging of subsurface structures of the region. The surface grid includes multiple grid cells with each having multiple vertices, and each of the multiple vertices is associated with a traveltime between the vertex and a first multiple subsurface points to be imaged. An interpolated traveltime associated with a first grid cell of the multiple grid cells and a ray tracing-based traveltime associated with the first grid cell are determined. A difference between the interpolated traveltime and the ray tracing-based traveltime is compared to a threshold. In response to determine that the difference is larger than the threshold, the first grid cell is subdivided into a first multiple smaller grid cells. The surface grid with the first multiple smaller grid cells is provided for seismic depth migration.