Elastic Reverse-Time Migration Using Stress-Displacement Wavefield Separation
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Solution Overview
Problem
Existing reverse-time migration methods in elastic media face challenges in accurately imaging subsurface structures due to waveform distortions and noise from mixed wavefields, particularly in complex geological settings like high-velocity layers, where general methods struggle to separate wavefields effectively without inducing waveform changes.
Innovation Solution
An elastic reverse-time migration system and method that uses stress-displacement relationships to decompose P-wavefields instead of divergence operators, combined with an absolute value function to improve image quality and minimize waveform changes during the separation process, ensuring accurate subsurface imaging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the divergence operator is used to separate P-wavefield, then wavefield separation is achieved, but waveform changing is induced
Solution Approach 1:
The patent introduces stress-displacement relationships as an intermediary mechanism to achieve wavefield separation without directly applying the divergence operator to displacement components. By using stress components as intermediaries, the separation process avoids the waveform changing that occurs when spatial differentiation is applied directly to displacement fields.
Solution Approach 2:
The patent replaces the traditional divergence operator approach with a stress-displacement relationship-based approach. Instead of using spatial differentiation on displacement components, the method uses the constitutive relationships between stress and displacement to achieve separation, thereby avoiding the harmful waveform changing effect.
2Measurement precision
If reverse-time migration is performed in elastic media, then subsurface structure imaging is improved, but mixed wavefields cause noise and distortion
Solution Approach 1:
The patent segments the mixed elastic wavefield into distinct P-wave and S-wave components by applying wavefield separation techniques. This segmentation allows each wave type to be processed independently, eliminating the noise and distortion caused by mixed wavefields while maintaining the benefits of elastic media imaging.
Solution Approach 2:
The patent extracts the P-wavefield component from the mixed wavefield using stress-displacement relationships. By taking out the P-wave component, the method eliminates the harmful interference from S-waves and other wave types, thereby improving imaging accuracy in elastic media.
3Ease of manufacture
If general reverse-time migration method is used, then computation is simplified, but subsurface structure representation is limited
Solution Approach 1:
The patent changes the fundamental parameters of the migration approach by introducing stress-displacement relationships and absolute value functions. These parameter changes enable the method to accurately represent complex subsurface structures like salt domes while maintaining computational feasibility through the use of elastic wave equations.
Data Source
AI summary
Provided is elastic reverse-time migration system and method using an absolute value function for improving the quality of subsurface structure images, and more particularly, elastic reverse-time migration system and method using an absolute value function for improving the quality of subsurface structure images capable of minimizing waveform changing by separating wavefields using stress-displacement relationships and improving accuracy of the subsurface structure images by applying the absolute value function to migration images.