Seismic Wavefield Attenuation Compensation via Q-Modeling
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Solution Overview
Problem
Seismic exploration faces challenges in accurately compensating for seismic attenuation, leading to poor resolution in depth-migrated images due to uncorrected phase dispersion and amplitude loss, especially in highly attenuating regions, which mispositions and unfocuses reflectors and diminishes the signal-to-noise ratio.
Innovation Solution
A method involving the compensation of recorded wavefields for amplitude attenuation by modeling the propagation of seismic data forward and backward through an earth model that accounts for phase and amplitude effects of attenuation, allowing for improved rendering of subsurface images.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional seismic data processing is used, then processing speed is maintained, but image resolution and accuracy deteriorate due to uncorrected phase dispersion and amplitude loss
Solution Approach 1:
The patent applies preliminary Q-compensation to the input seismic data before migration processing. By pre-correcting amplitude attenuation and phase dispersion effects using estimated Q-values, the data is prepared in advance to ensure accurate reflector positioning and focusing during migration, thereby improving image resolution without adding complexity to the migration algorithm itself
Solution Approach 2:
The patent introduces Q-compensation as an intermediary processing step between data acquisition and migration. This intermediate stage estimates attenuation parameters and applies corrective filtering to the seismic data, acting as a mediator that bridges the gap between raw attenuated data and the requirements for high-resolution imaging during migration
2Measurement precision
If Q-compensation is applied to correct amplitude attenuation, then image accuracy improves, but processing time increases due to additional modeling steps
Solution Approach 1:
The patent performs Q-compensation as a preliminary step before migration by estimating Q-values from the seismic data and applying amplitude and phase corrections in advance. This pre-processing approach ensures accurate reflector positioning during migration without requiring iterative Q-correction throughout the processing workflow, thereby reducing total processing time
Solution Approach 2:
The patent replaces complex iterative Q-compensation methods with a more efficient approach using estimated Q-values and analytical correction formulas. By substituting numerical iteration with direct calculation based on attenuation modeling, the method achieves accurate amplitude and phase correction while significantly reducing computational time
3Reliability
If attenuation effects are corrected in highly attenuating regions, then signal-to-noise ratio improves, but computational resources increase due to detailed modeling requirements
Solution Approach 1:
The patent applies Q-compensation specifically tailored to local attenuation characteristics by estimating Q-values that vary with depth and geological conditions. By adapting the compensation parameters to local subsurface properties rather than applying uniform correction, the method effectively restores signal-to-noise ratio in highly attenuating regions while optimizing computational resource usage through localized processing
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 enhances the accuracy of depth-migrated images by correcting for attenuation, leading to better positioning and focusing of reflectors and improved signal quality in subsurface imaging.
Implementation Method 1
the subsurface region has an absorption characteristic that dampens the recorded wavefield
Implementation Method 2
Uncorrected phase dispersion often leads to mis-positioned and unfocused reflectors
Data Source
AI summary
A method includes the steps of receiving a wavefield generated by reflections in a subsurface region and recorded by a plurality of seismic receivers and compensating the recorded wavefield for amplitude attenuation. The method further includes modelling a propagation of a source wavefield forward in time, from an initial time-state to a final time-state through an earth model that is representative of the subsurface region, wherein the modelling includes phase and amplitude effects of attenuation and modelling a propagation of the compensated recorded wavefield backward in time from a final time-state to an earlier time-state through the earth model, wherein the subsurface region has an absorption characteristic that dampens the recorded wavefield wherein the modelling includes phase and amplitude effects of attenuation.