First-Arrival Wave RTM Imaging With Excitation Amplitude Filtering
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Solution Overview
Problem
Existing seismic source wave reverse time migration (RTM) methods using excitation amplitude imaging condition struggle with imaging multi-path waves, leading to reduced imaging capability and noise interference, especially in complex media where multi-path wave amplitudes can be stronger than first arrival waves.
Innovation Solution
A method and system that identifies and preserves the maximum amplitude and time of first arrival waves during forward continuation, cross-correlates this with the receiver wave field, and superimposes these values to obtain RTM results, using methods like modified energy ratio (MCM) to reduce calculation complexity and noise interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If excitation amplitude imaging condition is used to reduce computer memory and improve computational efficiency, then imaging capability is limited because only one maximum amplitude and time are preserved at each grid node, preventing multi-path wave imaging
Solution Approach 1:
The patent segments the wave field into first arrival waves and multi-path waves by introducing a first arrival wave field identifier. This segmentation allows the system to preserve only the first arrival wave information at each grid node, thereby reducing memory usage and computational load while maintaining accurate imaging capability for primary reflections.
Solution Approach 2:
The patent extracts and preserves only the first arrival wave field identifier and corresponding amplitude information, discarding multi-path wave information. This extraction approach reduces the data storage requirement from preserving all wave fields to preserving only the essential first arrival wave data, thus improving computational efficiency without sacrificing imaging capability for primary targets.
2Adaptability or versatility
If multi-path waves are preserved for imaging by preserving several maximum amplitude values and corresponding times, then imaging capability is improved, but imaging noise increases and the problem becomes complex requiring targeted processing methods
Solution Approach 1:
The patent converts the harmful effect of multi-path waves into a benefit by using the first arrival wave field identifier to distinguish and preserve only the useful first arrival wave information. This approach transforms the problematic mixture of wave types into a purified signal set, eliminating imaging noise while maintaining the ability to image complex subsurface structures.
Solution Approach 2:
The patent applies different quality requirements to different wave components by preserving only the first arrival wave field identifier at each grid node. This local quality approach ensures that only the high-quality first arrival wave data is stored and used for imaging, while multi-path wave data is excluded, thereby preventing noise generation.
3Adaptability or versatility
If cross-correlation imaging condition is used instead of excitation amplitude, then multi-path waves can be imaged, but computer memory requirements increase and computational cost is high
Solution Approach 1:
The patent uses a disposable first arrival wave field identifier that is calculated once during forward continuation and then used for imaging without requiring storage of the entire wave field history. This approach provides multi-path wave imaging capability through first arrival wave preservation while keeping memory requirements and computational costs low, unlike cross-correlation imaging which requires storing complete wave fields.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enhances imaging capability and reduces noise interference, improving signal-to-noise ratio while minimizing computational resources by focusing on first arrival waves, thus achieving accurate underground medium imaging.
Implementation Method 1
perform forward continuation on the source wave field
Implementation Method 2
perform reverse time continuation on a receiver wave field
Implementation Method 3
cross-correlating the maximum amplitude of the source wave field with the receiver wave field at the same moment on each spatial grid node
Data Source
AI summary
A first arrival wave reverse time migration (RTM) method based on excitation amplitude includes the steps of acquiring calculation parameters of a seismic wave field, performing forward continuation on a source wave field, identifying a first arrival wave of the source wave field, and preserving the maximum amplitude and corresponding time of the first arrival wave; performing reverse time continuation on a receiver wave field; and cross-correlating the maximum amplitude of the source wave field with the receiver wave field at the same moment on each spatial grid node, and superimposing cross-correlation values to obtain an RTM result. In the present disclosure, by preserving the maximum amplitude and time of the first arrival wave, and cross-correlation imaging is conducted with the receiver wave field. The present disclosure can reduce the calculation amount and the interference of multi-path waves and improve a signal-to-noise ratio while ensuring the RTM imaging capability.