Seismic Multiple Separation Using Upgoing and Downgoing Wavefields
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Solution Overview
Problem
Existing seismic data processing methods struggle to effectively separate and utilize multiple reflections, which are considered noise, while they contain valuable subsurface information, especially in areas with poor primary illumination.
Innovation Solution
A method that includes identifying downgoing and upgoing wavefields, estimating first-order multiple reflection signals, and generating seismic images based on these signals to enhance data processing efficiency and accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional seismic data processing methods are used to separate primary and multiple reflection signals, then processing simplicity is maintained, but imaging accuracy deteriorates, especially in areas with poor illumination
Solution Approach 1:
The patent segments the seismic wavefield into downgoing and upgoing components using wavefield decomposition. This segmentation allows separate processing of primary reflections and multiple reflections, enabling accurate identification and imaging of first-order multiples while maintaining processing feasibility through systematic breakdown of the complex separation problem
Solution Approach 2:
The patent introduces an intermediary multiple elimination operator derived from the downgoing wavefield and direct arrivals. This operator acts as a mediator to predict and remove multiple reflections from the upgoing wavefield without requiring complex iterative processing, thereby improving imaging accuracy while controlling processing complexity
2Measurement precision
If multiple reflection signals are removed as noise, then primary signal quality is improved, but loss of complementary subsurface information occurs
Solution Approach 1:
The patent extracts first-order multiple reflection signals from the upgoing wavefield using a dedicated multiple elimination operator. By separating multiples as a distinct component rather than simply removing them as noise, the method preserves the ability to independently process and utilize multiple information for subsurface imaging while maintaining primary signal quality
Solution Approach 2:
The patent discards multiple reflections from the primary imaging process by eliminating them from the upgoing wavefield, but simultaneously recovers and images them separately using the extracted multiple components. This approach prevents information loss by ensuring multiples are preserved and utilized for additional subsurface imaging value
3Measurement precision
If conventional multiple removal techniques are applied, then processing efficiency is maintained, but imaging quality in challenging illumination conditions deteriorates
Solution Approach 1:
The patent performs preliminary wavefield decomposition into downgoing and upgoing components before multiple elimination. This preliminary action organizes the data in a way that facilitates efficient multiple removal through the intermediary operator, improving imaging quality in challenging illumination conditions while maintaining processing efficiency through pre-organized data structures
Solution Approach 2:
The patent replaces complex iterative multiple removal mechanics with a direct intermediary operator approach. By substituting traditional mechanical processing methods with a mathematically derived operator that directly eliminates multiples based on wavefield relationships, the method achieves both improved imaging quality and maintained processing efficiency
Data Source
AI summary
A method includes receiving seismic data including signals collected using a receiver, the seismic data representing a subsurface volume, identifying a downgoing wavefield and an upgoing wavefield in the seismic data, identifying direct arrivals in the downgoing wavefield, estimating at least first-order multiple reflection signals in the upgoing wavefield based on the downgoing wavefield, the upgoing wavefield, and the direct arrivals, and generating seismic images representing the subsurface volume based at least in part on the at least first-order multiple reflection signals.