Elastic Wave Stress Tensor Double-Dot Product Seismic Imaging
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Solution Overview
Problem
Current elastic reverse time migration imaging technologies cannot effectively separate shear wave stress and utilize the combined advantages of P-wave and S-wave exploration, leading to poor imaging quality and inaccurate risk prediction in oil and gas exploration.
Innovation Solution
An elastic wave stress tensor double-dot product seismic imaging method is developed, which solves the first-order velocity-stress equation using a staggered grid high-order finite difference method, decouples wavefields to obtain P-wave and S-wave components, and applies a double-dot product cross-correlation imaging condition to generate pseudo PP and PS scalar imaging results.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If traditional single P-wave component imaging technology is used, then the imaging process is simple, but the imaging quality is poor and the ability to predict oil and gas exploration risks is insufficient
Solution Approach 1:
The patent combines P-wave and S-wave exploration technologies into a unified imaging method. By integrating both wave types and utilizing their combined information through the stress tensor double-dot product imaging condition, the method achieves superior imaging quality and risk prediction capability compared to single P-wave imaging, while maintaining computational feasibility through the use of decoupled wave equations.
2Measurement precision
If the stress field is treated as a second-order tensor, then the theoretical accuracy is improved, but the existing scalar or vector correlation imaging conditions cannot be directly applied
Solution Approach 1:
The patent transforms the second-order stress tensor into a scalar imaging result by applying the double-dot product operation. This parameter transformation allows the use of simplified scalar correlation imaging conditions while preserving the theoretical accuracy benefits of tensor-based stress field representation. The imaging condition becomes computationally tractable by changing from tensor-to-tensor correlation to scalar-to-scalar correlation through the double-dot product.
3Measurement precision
If the decoupled wave equation method is used to calculate the receiver wavefield, then the particle vibration velocity vector wavefield can be obtained, but the shear wave stress separation is still not achieved without crosstalk
Solution Approach 1:
The patent introduces the stress tensor as an intermediary between the particle vibration velocity field and the final imaging result. By computing the stress tensor from the decoupled wave equations and then applying the double-dot product imaging condition, the method effectively separates shear wave stress components without crosstalk. The stress tensor acts as a mediator that transforms the velocity field information into separated stress components that can be reliably imaged.
Data Source
AI summary
The embodiment of the disclosure relates to an elastic wave stress tensor double-dot product seismic imaging method and device. The method comprises: obtaining a decoupled particle vibration velocity vector wavefield by utilizing the existing decoupled wave equation method for the receiver wavefield; then obtaining a decoupled pseudo-stress wavefield by constructing the decoupled pseudo-stress equation by using the obtained decoupled particle vibration velocity vector wavefield; and finally computing a source second-order stress tensor wavefield and the decoupled receiver second-order stress tensor wavefield by using the double-dot product cross-correlation imaging condition algorithm, to obtain the final scalar imaging results. With the embodiment of the present disclosure, the combined P-wave and S-wave stress exploration can be realized, therefore, the obtained imaging results can be used to accurately predict the risk of gas exploration.