NUMERICAL SIMULATION OF SEISMOELECTROGRAMS

PATRICIA M. GAUZELLINO; JUAN E. SANTOS; FABIO I. ZYSERMAN

MECANICA COMPUTACIONAL

AMCA

Lugar: Buenos Aires; Año: 2010 vol. 29 p. 2309 - 2322

The conversion of energy between seismic and electromagnetic wave fields involves relative movement of ions at the rock-fluid contact surfaces in the pore space, described by Biot’s equations ofmotion in poroviscoelastic media coupled with Maxwell’s equations. The numerical simulation of seismoelectrograms allows to analyze full-waveform coupled seismoelectromagnetic wave propagation influid-saturated porous media. It is possible to observe two different responses: the coseismic response with the same waveform as a seismic wave and the interface response that occurs when a seismic waveencounters a contrast in electrical or mechanical material properties. The proposed algorithm calculates the electromagnetic field from seismic displacements, particularly fluid displacements, using the finiteelement method employing a parallelizable non-overlapping domain decomposition technique, which is required due to the high computational cost of the problem. The seismoelectric method allows the possibility of detecting very thin impermeable layers, permeable fractures and interfaces between differentformations due to changes in permeability or saturant fluids. The 2D implementation of the procedure illustratesidentification of subsurface heterogeneities when applied to different targets and source-receiver configurations.