Starting Research Position, Project Team MAGIQUE-3D
email : email@example.com
Tel : +33 5 40 17 52 09
I am developing modeling and imaging methods to investigate the Earth’s internal structure. Obtaining and improving images of the Earth’s interior is key to better understanding our planet: What is its internal structure? What is its history? Its mineral composition? The geodynamical processes involved as its cools? Detailed imaging of the upper part of the Earth’s crust is strategically important as it contains most of the natural resources that are vital to modern society. Further, reliable methods for imaging the subsurface are crucial for solving geotechnical problems. For example, imaging is essential for environmental-site characterization, verification of remediation practices, and the construction of transportation facilities and infrastructure.
Imaging and Inversion
I am developing a novel imaging method called Box-Tomography for performing local imaging using remote data. Box-Tomography allows for fast and accurate imaging of remote targets buried inside the Earth, where neither seismic sources nor receivers are necessarily present. Box-Tomography rely on seismic records (full-waveforms) and combines wave propagation modeling with wavefield extrapolation techniques for better efficiency.
Wave Propagation in Porous Materials
I am interested in the physical mechanisms responsible for the attenuation and dispersion of seismic wave in porous materials. Through numerical and analytical studies, I establish links between the physical properties of rocks and the attenuation and dispersion of seismic waves. For example, for a material having a self-affine (fractal) distribution of elastic properties, I showed that frequency dependence in the attenuation is controlled by a single parameter that is directly related to the fractal dimension of the material. Understanding how the hydro-physical properties of rocks are linked to the attenuation and dispersion of seismic waves is a key step in the longstanding quest to invert for (i.e., to image) the hydro-physical properties of rocks from seismic data.
Slow Immiscible Fluid Migration
Driven by the need for modeling wave propagation through realistic media having multiphasic fluid distribution, I became accidentally interested in invasion percolation models. Invasion percolation (IP) is a cluster growth model introduced in the 1980s for modeling quasi-static (i.e. slow) Immiscible fluid migration in porous media. This process occurs naturally in various contexts, for example, when oil, water or gas migrate through reservoir rocks. Though IP is conceptually simple and can be implemented with ease, modeling fluid migration through large enough systems is computationally intense and hardly doable with existing algorithms. To overcome this difficulty, I am developing fast algorithms for solving the invasion percolation problem.
Mechanical Properties of Rocks
Even though nowadays my research concentrates on numerical and analytical approches, I have spend a few years in during career working on experimental projects. For example, I designed and constructed a micro-indentation scanner to measure fluctuation in the elastic properties of natural rocks. This micro-indentation scanner is now available to researchers at the Lawrence Berkeley Laboratory. It has been used successfully to quantify the spatial fluctuation in the mechanical properties of sandstones. Such data is key to feed the numerical simulations (e.g. to model wave propagation) with realistic input parameters.