The Laboratory of Modeling Methods and Computational Geophysics of the Civil Engineering Program at COPPE/UFRJ focuses on the development of numerical analysis tools for geophysics and seismic modeling.

Maintaining oil self-sufficiency is currently the biggest challenge facing the Brazilian oil industry. To be sustainable, Petrobras will need to discover another Petrobras by 2030. The great difficulty lies in obtaining accurate geological information, considering that our producing and most promising sedimentary basins are under the sea. In this context, geophysical methods, especially seismic methods, are of fundamental importance. They are essential tools for obtaining reliable information about the subsurface. The great challenge, however, lies in obtaining a reliable image of the subsurface geology, thus reducing the exploration risk.

Wave Propagation is one of the most complex and interesting topics in science and is the subject of study in various areas of knowledge such as Physics, Engineering (Civil, Mechanical, Electrical, Oceanic, Biomedical, Nuclear, etc.), Geophysics, Medicine, Astronomy, Atmospheric Sciences, among others. Currently, numerical approaches to problems involving this topic have become increasingly attractive (compared to experimental approaches), as new technological advances and the emergence of new hardware architectures have made it possible to refine the mathematical models used in such simulations, obtaining increasingly reliable solutions and at an ever shorter execution time for complex industry problems.

Some general PDE solution techniques that apply to wave propagation modeling in various areas of knowledge, in particular seismic methods, are the Finite Difference Method (FDM), the Finite Element Method (FEM), and Integral Methods: The Finite Difference Method (FDM), the Finite Element Method (FEM), and Integral Methods. The ‘Integral Methods’ include the Kirchhoff integral equations and other more general procedures known in the literature as Boundary Element Methods, from which the Explicit GREEN Functions (ExGA) technique is derived. The computer programs developed using these techniques use parallel processing resources due to the high number of unknowns, especially in 3D analysis.

Computer algorithms and transform-based techniques have been developed to model dynamic soil-fluid-structure interaction. The modeling techniques of this topic are common to those of Geophysics, although the range of frequencies involved is different.

Modeling algorithms are used in the analysis of velocity models, where Reverse Migration in Time is considered, since the phenomenon of wave propagation is present in both. In Modeling, wave propagation occurs in the direct direction of time, while in Reverse Time Migration, there is a “depropagation”, in the reverse direction of the time axis, of the recorded wave field containing information about the layers and interfaces of a given geological model. In Migration, the recorded wavefield is transformed using appropriate methodologies into correctly positioned images of the sub-surface reflectors. Classical GEOPHYSICS migration techniques based on integral equations (Kirchhoff migration), diffraction tomography (Born approximations) Phase Shift Plus Interpolation (PSPI), etc. are also considered. General Inverse Problem solution techniques are also included in this area of research with the aim of looking for alternative and/or complementary techniques for producing deep images of seismic sections, with a view to identifying new oil reservoirs, as well as monitoring and evaluating existing reservoirs. Similar methodology can also be applied to the identification and monitoring of aquifer reservoirs, the identification of cracks in structural systems (dams, weld seams, etc.) among other cases, and in specific Civil Engineering problems such as soil-fluid-structure interaction, indoor and outdoor acoustics, etc.

In the last decade, work on seismic methods at the PEC has made substantial progress in applications in petroleum GEOPHYSICS, due to the intense collaboration of PETROBRAS professionals and the participation of professors in the development of the Applied GEOPHYSICS Thematic Network.