| Abstract: | Large memory computers create new possibilities for seismic interpretation in well-drilled areas, and more generally in problems involving deep sources. Records obtained by well-to-surface, surface-to-well and/or well-to-well propagation contain a large amount of information, owing to the great number of seismic rays travelling throughout the subsurface. This paper considers two successive steps: — direct case: computation of the first arrival times of seismic rays propagating through a two-dimensional subsurface with given vertical and horizontal velocity variations; — inverse case: computation of a two-dimensional velocity distribution, knowing the travel times of seismic rays through the subsurface. A computer program has been elaborated to solve both direct and inverse problems. There are no difficulties with the direct case; a certain number of uncertainties remain with the inverse case. |
