An algorithm for 3D seismic inversion

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

MECANICA COMPUTACIONAL

AMCA

Lugar: Cordoba; Año: 2001 vol. 20 p. 569 - 576

We present an algorithm to solve an inverse problem originated inseismic exploration. In order to briefly describe the geophysicaltechique, we can say that whiledrilling a borehole, the drill-bit generates a signal asumed asa seismic source. The wavefront  propagates through the earth, and the direct and reflected waves at  the different interfaces are  recorded at a line of geophones laid out on the ground. Thus we aim to estimate the wave speeds of the different formations within the earth interior from the measurements at the geophone positions. The forward model is formulated, assuming cylindrical symmetry, by means of the displacements of an elastic solid, and discretized usingthe Morley mixed finite elements. For the inverse problem, castedas a minimum squares one,  we use a quasilinearization algorithm, which allows for a late discretization of the problem. A parallel version of the algorithm is used to solve the included numerical example.