# Laboratory of Module an Computational Geophysics - LAMEMO

## Summary

The objective of the Computational Geophysics Nucleus of the Civil Engineering Program at COPPE/UFRJ is to develop numerical analysis tools for Geophysics and seismic modeling.

Currently, the main challenge of the Brazilian Oil Industry is to sustain oil self-sufficiency. To be sustainable, Petrobras must find another Petrobras until 2030. Considering that our productive sedimentary basins are offshore, the main problem is to obtain precise geological information. Thus, the geophysical methods, particularly the seismic method, are very important. They are essential tools to obtain subsurface reliable information. The great challenge is to obtain a reliable image of subsurface geology to reduce exploratory risks.

Wave Propagation is one of the most interesting and complex subjects in Science and it is studied in several areas of knowledge such as Physics, (Civil, Mechanical, Electric, Oceanic Biomedical, Nuclear, etc.) Engineering, Geophysics, Medicine, Astronomy, Atmospheric Sciences, among others. Currently, numerical approaches of problems on this subject are preferred to experimental approaches, because new technological advances and the development of new hardware architectures allowed bettering the mathematical models employed on such simulations, obtaining increasingly reliable solutions and shorter execution times for complex industry problems.

Velocity model depth slice at a depth of 2650m (Boechat 2007)

Some of EDP solution general techniques applied to wave propagation modeling on several knowledge areas particularly seismic methods are: Finite Difference Method (MDF), Finite Element Method (MEF), and Integral Methods. “Integral methods” include Kirchhoff integral equations and other more general procedures such as Boundary Element Methods from which the Explicit Green Functions (ExGA) derive. The computational programs developed using those techniques employ parallel processing resources due to the high number of variables, mainly in 3D analyses.

Computational algorithms and transform based techniques are developed for Soil – Fluid – Structure dynamic interaction modeling. These modeling techniques are similar to those of Geophysics, though with a different frequency range.

Modeling algorithms are used on velocity model analysis, where reverse-time migration is considered once the wave propagation phenomenon is present in both. Wave propagation occurs on a direct relation with time on Modeling whereas on Reverse-Time Migration a depropagation of the wavefield recorded containing information on the layers and interfaces of a certain geological model occurs backwards to the time axis. In Migration, the recorded wavefield is transformed through adequate methodologies on images correctly positioned of the subsurface reflectors. Classical GEOPHYSICS migration techniques based on integral equations (Kirchhoff migration), diffraction tomography (Born Approximation), Phase Shift Plus Interpolation (PSPI), etc. are also considered. General techniques for the solution of Inverse Problems are included on this Research Area focusing on finding alternative and / or complementary techniques to produce depth images of seismic sections, aiming the identification of new oil reservoirs, and the monitoring and assessment of those already existent. Similar methodology may be applied for aquifer reservoir monitoring and assessment, crack identification on structural systems (dams, weld seams, etc.) among others, and on specific problems of Civil Engineering such as soil – fluid – structure interaction internal and external environment acoustics, etc.

During the last decade PEC works on seismic methods advanced considerably on oil GEOPHYSICS applications due to the strong collaboration of PETROBRAS professionals and faculty participation on the APPLIED GEOPHYSICS Subject Network.

Migrated cube depth slice of at a depth of 2650m (Boechat 2007)

## Infrastructure

Currently NGC occupies a 50m^{2} area at block B and a 150m^{2} area at block I shared with LAMEC. New facilities will occupy a 330m^{2} area at the new building being constructed by PEC.

## Faculty

**PROFESSORS**

Prof. José Antonio Fontes Santiago

Prof. José Claudio de Faria Telles

Prof. Luiz Fernando Taborda Garcia

Prof. Roberto Fernandes de Oliveira

Prof. Webe João Mansur (professor responsável)

Prof. Eduardo Gomes Dutra do Carmo (professor titular – PEN)

Prof. Carlos Eduardo Parente Ribeiro (professor adjunto – PENO)

Prof. Jules Ghislain Slama (professor – PEM)

**PROFESSORS AND RESEARCHERS WHO PERFORM LABEST ACTIVITIES**

Ana Ibis de Abreu Rojas D.Sc.( bolsa PNPD CNPq)

Cid da Silva Garcia Monteira M.Sc. (Fundação COPPETEC)

Cleberson Dors, D.SC. (Fundação COPPETEC)

Marcio de Araújo Martins, M.Sc. (Fundação COPPETEC)