Variable Aperture Estimation via Bottom-Up Ray Tracing
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Solution Overview
Problem
Current seismic prospecting methods, particularly Full Wavefield Inversion, face inefficiencies due to uniform aperture estimations across all gathers, leading to inadequate computational resource utilization and introduction of artificial noise, which impede accurate subsurface imaging and hydrocarbon identification.
Innovation Solution
The method employs bottom-up ray tracing to estimate unique apertures for each gather based on origin coordinates, storing these in a table for improved subsurface imaging, allowing for variable aperture calculations that match survey data complexities, thereby optimizing computational efficiency and reducing noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If uniform aperture estimation is used for all gathers, then the method is simple to implement, but computational resources are inadequately utilized and artificial noise is introduced
Solution Approach 1:
The patent applies local quality by estimating unique apertures for each gather based on local dip characteristics. Instead of using a uniform aperture for all gathers, the method calculates aperture values tailored to each specific gather's dip angle, thereby optimizing computational resource utilization for each local region while maintaining ease of implementation through automated calculation.
2Device complexity
If uniform aperture estimation is used for all gathers, then the processing is computationally simpler, but artificial noise is introduced into the inverted data
Solution Approach 1:
The patent eliminates artificial noise by applying local quality principles - each gather receives an aperture estimation matched to its specific dip characteristics. This prevents the introduction of swing noise that occurs when inappropriate uniform apertures are applied to gathers with different dip angles, while the automated calculation keeps processing complexity manageable.
Solution Approach 2:
The patent applies preliminary action by calculating aperture estimations for all gathers before performing the actual inversion process. This pre-calculation ensures that each gather has its optimized aperture ready, preventing noise introduction during inversion while avoiding the need for complex real-time adjustments during processing.
3Ease of manufacture
If experimental or constant aperture selection is used, then the method is easier to implement, but it does not reliably match aperture to survey data complexities
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting aperture values based on dip angle parameters for each gather. Instead of using fixed or experimentally selected apertures, the method calculates aperture as a variable parameter that changes according to the specific dip characteristics of each gather, thereby achieving both ease of implementation through automated calculation and high precision in aperture matching.
Data Source
AI summary
A method and apparatus for imaging seismic data includes obtaining an initial model of a subsurface formation, wherein the model includes a plurality of nodes that form at least part of a grid; an initial dip value for the nodes; and a set of origin coordinates for each of the nodes; performing bottom-up ray tracing for each node in the model, resulting in a set of arrival coordinates for each node; identifying a plurality of gathers from the seismic data; for each gather: calculating a set of midpoint coordinates; defining a midpoint vicinity surrounding the set of midpoint coordinates; identifying the nodes having arrival coordinates within the midpoint vicinity; and estimating a unique aperture for each of the gathers based on the respective origin coordinates; storing the estimated apertures in a table; and generating a subsurface volume or image with subsurface reflectors determined with apertures of the respective gathers.