ESTIMATION OF REFLECTOR PARAMETERS BY THE VIRTUAL IMAGE TECHNIQUE*

Abstract

AbstractThe seismic interpretation process generally exploits three of the following independent basic assumptions: Input quantities are obtained by simplification of measured data (travel time curves). 2. The geological model contains only a few parameters (for example, plane interfaces and constant interval velocities). 3. Approximate transformations may be applied. The first two are related to the simplification of the phenomena and enhance their essential features. The transformation which establishes relations between simplified data and model is required to be unique, stable, and sufficiently accurate.Practically, the travel time curves are almost exclusively regarded as hyperbolas. We also accept this approximation.The paper presents a simple recursive algorithm for the evaluation of the depth and dip of plane reflectors and the interval velocities.It is a simple fact, that there exists a unique relationship between three hyperbolic parameters and a homogeneous dipping layer. Accordingly, two layers can be replaced by a single layer and the parameters of the lower boundary can be estimated when the upper one is known, initiating virtual shotpoints and geophone points (virtual surface). So, the case of multilayered media can be reduced in sequential steps to the case of a single homogeneous layer using a stripping type procedure.Some synthetic model examples are provided to demonstrate the abilities of the algorithm.