Time-Variant Boundary Conditions for Seismic Wavefield Modeling
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Solution Overview
Problem
Seismic exploration faces challenges in modeling wavefields using finite computational domains, particularly in emulating an infinite wavefield while managing coherent boundary reflections.
Innovation Solution
The technique involves varying boundary conditions with respect to time during wavefield generation, either by moving the computational domain to induce a Doppler shift or using time-variant random boundaries to isolate and minimize coherent reflections, thereby shifting energy outside the frequency range of interest.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a finite computational domain is used to model wave propagation, then computational resources are conserved and modeling becomes feasible, but coherent boundary reflections are introduced that contaminate the wavefield
Solution Approach 1:
The boundary conditions are made dynamic by varying them with respect to time during wavefield generation. Specifically, the boundary conditions change from reflective at early times to absorptive at later times, allowing the computational domain to effectively expand as waves propagate. This dynamic adaptation eliminates coherent boundary reflections while maintaining computational feasibility within a finite domain.
Solution Approach 2:
The boundary condition parameters are changed over time during the modeling process. The boundary transitions from having reflective properties to having absorptive properties as a function of time, which prevents coherent reflections from contaminating the wavefield while allowing the use of a finite computational domain.
2Object-affected harmful factors
If boundary conditions are made absorptive to reduce reflections, then coherent boundary reflections are reduced, but wavefield accuracy deteriorates due to energy loss at boundaries
Solution Approach 1:
The boundary conditions are applied periodically or sequentially in different phases of the wavefield generation process. Absorptive boundary conditions are activated only after the primary wavefield has been established and propagated, ensuring that energy is not absorbed during critical early stages while still preventing reflections at later stages when waves approach the boundaries.
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 effectively regulates coherent boundary reflections, enhancing the accuracy of wavefield modeling by isolating boundary interactions and reducing coherent energy correlations, which improves imaging and velocity modeling in seismic data analysis.
Implementation Method 1
moving the computational domain to induce a Doppler shift
Data Source
AI summary
A technique includes receiving data indicative of a wavefield in a processor-based system and processing the data on the processor-based system to generate a modeled wavefield. The processing includes varying boundary conditions of the modeled wavefield with respect to time to regulate coherent boundary reflections in the modeled wavefield.