Diffraction Imaging via Pseudo Dip-Angle Gather
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for generating diffraction images from seismic data are inefficient due to the weakness of diffraction energy signals and the inaccuracies caused by ray theory-based approaches, which fail to represent wave phenomena well in complex subsurface media.
Innovation Solution
The method involves converting shot gathers into plane-wave gathers using a linear Radon transform, decomposing receiver-side wavefields with a recursive Radon transform, and applying a windowed median filter to extract diffraction energy, while using the acoustic wave equation for extrapolation and imaging conditions to generate pseudo dip-angle gathers, thereby separating diffraction and reflection energy effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If ray theory-based approaches are used to generate diffraction images, then computational complexity is reduced, but measurement precision and reliability deteriorate due to inability to represent wave phenomena accurately in complex subsurface media
Solution Approach 1:
The patent replaces ray theory-based mechanical approximation with wave equation-based numerical simulation. The wave equation approach (using finite difference or spectral methods) accurately models wave propagation, reflection, and diffraction phenomena in complex subsurface media, substituting the simplified mechanical ray tracing model with a more rigorous physical model that captures true wave behavior.
Solution Approach 2:
The patent changes the fundamental parameters of the imaging approach by transitioning from ray-based geometric optics parameters to wave-based physical parameters. This includes using wavefield extrapolation with proper boundary conditions and applying wave-equation-based migration algorithms that account for frequency-dependent propagation effects, thereby improving image accuracy while managing computational complexity through efficient numerical methods.
2Productivity
If conventional migration methods are used, then processing speed is maintained, but manufacturing precision deteriorates due to mixing of diffraction and reflection energy
Solution Approach 1:
The patent applies segmentation by separating diffraction energy from reflection energy through dip-angle filtering. The wavefield is decomposed into different dip-angle components, allowing selective extraction of diffraction events (which exhibit characteristic flat responses in dip-angle domains) from reflection events (which show curved responses). This segmentation enables precise diffraction imaging while maintaining processing efficiency through targeted filtering rather than full reprocessing.
Solution Approach 2:
The patent introduces dip-angle gathers as an intermediary domain for processing. By transforming the wavefield into the dip-angle domain, applying filtering operations to isolate diffraction energy, and then transforming back to the spatial domain, the method acts as an intermediary step that separates mixed energy types without requiring complete reprocessing, thereby maintaining productivity while improving precision.
3Quantity of substance
If diffraction energy is enhanced through conventional filtering, then signal strength increases, but manufacturing precision worsens due to loss of spatial resolution
Solution Approach 1:
The patent transitions to another dimension (dip-angle domain) for filtering operations. Instead of applying conventional spatial or frequency domain filters that blur spatial details, the method transforms to the dip-angle domain where diffraction and reflection energies are separated by their geometric characteristics, applies filtering in this alternative dimension, and then transforms back. This preserves spatial resolution while enhancing diffraction signal strength.
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 produces accurate and efficient diffraction images by reducing computational costs and improving resolution, allowing for the clear identification of subsurface features like faults and fractures.
Implementation Method 1
using the acoustic wave equation for extrapolation and imaging conditions to generate pseudo dip-angle gathers
Implementation Method 2
converting shot gathers into plane-wave gathers using a linear Radon transform
Implementation Method 3
decomposing receiver-side wavefields with a recursive Radon transform
Implementation Method 4
applying a windowed median filter to extract diffraction energy
Data Source
AI summary
Systems, methods, and apparatuses for generating a subsurface image using diffraction energy information are disclosed. The systems, methods, and apparatuses may include converting a shot gather into one or more plane-wave gather using a Radon transform. The plane-wave gathers may be extrapolated into source-side wavefields and receiver-side wavefields and further generate a pseudo dip-angle gather. The diffraction energy information may be extracted from the pseudo dip-angle gather, and an image containing subsurface features may be generated from the extracted diffraction energy information. The receiver-side wavefields may be decomposed using a recursive Radon transform.