Numerical Simulation of 2D Seismic Wave Propagation in Isotropic and Anisotropic Mediums Applied to a Zero-Offset VSP of the Isleño Field, Eastern Venezuela Basin

Abstract

For a full wave inversion it plays an important role to know the medium (isotropic, anisotropic, poroelastic, etc.) that best fits the observed data so the goal of this work, which is part of a larger FWI project, is to study which direct problem allows us to describe better the set of observed data that are available to us. To this end, 2D numerical simulations of seismic wave propagation were carried out using a staggered grid finite difference approach to simulate the acquisition of a zero offset VSP. The synthetic data (d) was compared with the data (dobs) of a zero offset VSP acquired in the Isleño field, Greater Temblador Area in the Monagas State, Venezuela. The physical models studied were wave propagation in isotropic and VTI anisotropic media. The results of the study show three aspects to stake. First, the signal decay for the vertical component for both the real and simulated data is similar. Second, when comparing the vertical component of the real and synthetic data, it is observed that a signal recorded at 996 m the correlation was 0.75 for the isotropic medium and 0.81 for the VTI anisotropic medium for direct waves. Finally, the third, the comparison for the horizontal component recorded at the same depth shows a correlation of 0.40 for the isotropic medium model and 0.34 for the VTI anisotropic medium for direct waves. The results obtained allow us to deduce that in the case of performing a full wave inversion in the land seismic data acquired in the Isleño field, it is recommended that it be of the anisotropic full wave inversion type to obtain better results.