Abstract

The use of genetic algorithms for solving geophysical inverse problems has become popular because of the availability of high performance computers. AVA (Amplitude variation with angle) inversion is increasingly used in oil and gas industry for estimation of elastic parameters from prestack seismic data. In this article we present an inversion algorithm based upon real coded genetic algorithm (RCGA) for estimating compressional and shear wave velocities and densities from angle gathers. The forward modeling uses the concept of elastic impedance for calculation of synthetic angle gathers. The starting model for inversion is derived from the velocity analysis on CMP gathers. The CMP gather is converted to angle gathers for comparison of observed and synthetic data. A one-dimensional variation of elastic parameters is assumed at the given CMP location. The usefulness of the algorithm is demonstrated by applying it to some complex synthetic data sets. Parallel implementation of the code is carried out on teraflop computer of Centre for Development of Advanced Computing (C-DAC), called PARAM Padma.