Pseudo-Reflectivity Imaging Using FWI-Migration Frequency Bridging
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Solution Overview
Problem
Conventional pseudo-reflectivity images suffer from limited resolution due to the frequency gap between inversion-based and migration-based seismic imaging processes, leading to the loss of fine subsurface structure details.
Innovation Solution
A method and apparatus that combines full waveform inversion (FWI) and migration-based processes to generate high-resolution pseudo-reflectivity images by constructing a velocity model, performing seismic migration, computing polarized normal vectors, and combining them with a velocity gradient to produce images at higher frequencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional inversion-based or migration-based seismic imaging processes are used, then the imaging process is relatively simple, but the resolution and illumination of subsurface structures are limited due to frequency gap
Solution Approach 1:
The patent combines full waveform inversion (FWI) and migration-based seismic imaging processes into a unified workflow. The FWI process generates a velocity model and velocity gradients, which are then integrated with migration-based imaging to produce pseudo-reflectivity images. This merging allows the system to achieve high resolution (benefit of FWI) while maintaining computational feasibility (benefit of migration), effectively resolving the contradiction between resolution and complexity.
2Measurement precision
If high-frequency seismic data processing is performed to preserve fine subsurface details, then the resolution improves, but the computational cost and processing time increase significantly
Solution Approach 1:
The patent performs full waveform inversion first to pre-compute the velocity model and velocity gradients before the migration-based imaging step. This preliminary action prepares all necessary high-resolution information in advance, allowing the subsequent imaging process to operate efficiently without repeated iterative computations, thereby reducing overall processing time while maintaining high resolution.
Solution Approach 2:
The velocity model and velocity gradients computed from FWI serve as intermediaries that bridge the inversion-based and migration-based processes. These intermediaries contain the high-frequency information needed for fine detail resolution, allowing the migration step to achieve high resolution without performing computationally expensive high-frequency inversion, thus reducing processing time.
3Loss of information
If conventional pseudo-reflectivity imaging is used, then the processing is more straightforward, but fine subsurface structure details are lost due to frequency limitations
Solution Approach 1:
The patent changes the frequency parameter by utilizing the velocity model and velocity gradients from FWI, which contain high-frequency information, in the migration-based imaging process. This parameter change enables the preservation of fine subsurface details that would be lost in conventional low-frequency pseudo-reflectivity imaging, while the integrated workflow manages the increased complexity through systematic integration of processing steps.
Data Source
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AI summary
A method for generating a high-resolution pseudo-reflectivity image of a subsurface region includes receiving seismic data associated with a subsurface region and captured by one or more seismic receivers, constructing a velocity model of the subsurface region based on the received seismic data, performing a seismic migration of the received seismic data based on the constructed velocity model to obtain migrated seismic data, computing polarized normal vectors associated with one or more subsurface reflectors of the subsurface region based on the migrated seismic data, and generating a pseudo-reflectivity image of the subsurface region based on both the computed polarized normal vectors.