Marine Seismic Imaging Using Separated Upgoing and Downgoing Wavefields
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Solution Overview
Problem
Current seismic imaging techniques face challenges with inadequate illumination and poor resolution, as well as crosstalk contamination in marine seismic surveys, which affect the accuracy of subterranean formation imaging.
Innovation Solution
The process involves separating recorded pressure and vertical velocity wavefields into upgoing and downgoing components, using these wavefields with a migration operator to generate seismic images, and iteratively updating the images to reduce crosstalk artifacts and enhance resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional seismic imaging techniques are used, then the imaging process is simple, but the illumination and resolution are inadequate
Solution Approach 1:
The wavefield is segmented into upgoing and downgoing components using separation operators. This segmentation allows selective processing of different wavefield components to improve imaging resolution while managing computational complexity through targeted operations on specific wavefield portions.
Solution Approach 2:
The method transitions from conventional single-wavefield imaging to a multi-dimensional approach by separating and processing upgoing and downgoing wavefields independently, then combining them through iterative updates. This dimensional expansion in wavefield processing enhances illumination and resolution.
2Manufacturing precision
If multiple reflected wavefields are used to enhance imaging, then resolution improves, but crosstalk artifacts increase
Solution Approach 1:
The method converts potentially harmful multiple reflected wavefields into beneficial imaging components. By separating and iteratively processing upgoing and downgoing wavefields, the method transforms multiple reflections that could cause crosstalk into enhanced illumination, improving resolution while managing artifacts through controlled iterative updates.
Solution Approach 2:
The iterative update mechanism implements feedback by using previously processed wavefield components to refine subsequent imaging results. This feedback loop allows the method to progressively improve imaging quality while monitoring and controlling crosstalk artifacts through repeated refinement cycles.
3Illumination intensity
If wavefield separation is performed, then illumination improves, but processing time increases
Solution Approach 1:
Wavefield separation into upgoing and downgoing components is performed as a preliminary action before the main imaging process. This preliminary separation enables more efficient subsequent processing by organizing wavefield data in a manner that improves illumination while reducing the computational burden of the iterative imaging steps.
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 results in improved illumination, resolution, and reduced crosstalk artifacts in seismic images, providing more accurate subterranean formation imaging compared to conventional methods.
Implementation Method 1
The acoustic impulse is a sound wave that spreads out in all directions. A portion of the impulse that travels down through the water and into a subterranean formation propagates as a sound wave within the subterranean formation.
Implementation Method 2
At each interface between different types of rock and sediment, a portion of the sound wave is refracted, a portion is transmitted, and another portion is reflected into the body of water to propagate toward the water surface.
Implementation Method 3
Each streamer contains seismic receivers or sensors that detect pressure and/or particle motion wavefields of the sound waves reflected into the water from the subterranean formation.
Data Source
AI summary
This disclosure describes processes and systems for generating a seismic image of a subterranean formation from recorded seismic data gathers obtained in a marine seismic survey of the subterranean formation. The seismic data comprises recorded pressure and vertical velocity wavefields that are used to separate the recorded pressure wavefield into upgoing and downgoing pressure wavefields. A seismic image is computed from the subterranean formation based on a product of the downgoing pressure wavefield and a migration operator applied to the upgoing pressure wavefield. The downgoing pressure wavefield is a boundary source wavefield and the upgoing pressure wavefield is boundary receiver wavefield of the migration operator. The seismic image is iteratively updated by computing a residual seismic image based on the upgoing pressure wavefield and adding the residual seismic image to the seismic image. The final seismic image displays increased illumination and reduced crosstalk artifacts compared to conventional seismic imaging techniques.