Towards high-order numerical simulations of conducting poroelastic media with time-harmonic waves. Part I : poroelastic case
Abstract
The sustainable exploration and exploitation of the natural resources of the Earth are fundamental for the socio-economic development. Hence, obtaining accurate images of water, mineral and energy sources below the surface is a key step for their management and exploitation. In order to improve the accuracy of the images, it is now necessary to consider more complex models such as conducting poroelastic media and to develop efficient solvers able to reproduce accurately waves propagation in such media. When a seismic wave propagates in a porous media, electromagnetic (EM) wavefields are generated through seismoelectric conversion. The EM contribution is twofold:
(a) a co-seismic transient electric field supporting the seismic wave; (b) an electromagnetic wave generated by conversion of seismic wave at the interface between two different porous media. As a follower of seismic, the first EM wave does not carry more information than seismic whereas the converted EM waves at interfaces have potentially huge application in near-surface Geophysics. Actually, a contact water-oil would generate an EM seismo-electric conversion where the seismic field would be blind to such an interface. The quantitative understanding of the conversion at interfaces is still poorly known and has only been seldomly observed in the field. To the best of our knowledge, the numerical simulation of this phenomenon has never been achieved with high-order finite element methods. As a first step, we have developed a piece of software for poroelastic media. To ease the numerical implementation, we work in the frequency domain. We can easily include physical parameters that depend non-linearly on the frequency and we avoid the issue of adapting time step and mesh size required when working in time domain. We have developed a new Hybridizable Discontinuous Galerkin method. This allows us to reduce the computational costs by considering only degrees of freedom on the squeleton of the mesh. We have validated the numerical method thanks to comparison with analytical solutions. We have obtained numerical results for 2D realistic poroelastic media and conducting poroelastic media is under investigation. Validations are ongoing on the basis of comparisons with laboratory experiments and numerical simulations performed with another software package.- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFM.T52C..12M
- Keywords:
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- 0545 Modeling;
- COMPUTATIONAL GEOPHYSICS;
- 0560 Numerical solutions;
- COMPUTATIONAL GEOPHYSICS;
- 1932 High-performance computing;
- INFORMATICS;
- 3275 Uncertainty quantification;
- MATHEMATICAL GEOPHYSICS