Sensibility Analysis Of The Multifocusing Traveltime Approximation

The zero-offset (ZO) seismic section can be simulated by properly stacking a set of common-offset seismic<br>sections, using conventional procedures like the well know Common-Midpoint (CMP/DMO) method. In the recent<br>past years, a new stack technique for ‘simulating a ZO section was proposed, the so-called Multifocusing Stack<br>(MFS). This technique can be used for arbitrary configuration and number of source and geophone pairs.The<br>traveltime approximation of the stack formula depends on three wavefront parameters: (1) the radius of<br>curvature of the NIP wave, Rnip ; (2) the radius of curvature of the normal wave, Rn ; and (3) the emergence<br>angle of the reflection normal ray, βo . All these three wavefront parameters are obtained as solution of a inverse<br>problem. They provide the best fitting of the stack surface, the so-called Common-Reflection-Surface (CRS), on<br>the observed multicoverage seismic data. In this paper we present a sensibility analysis of the multifocusing<br>traveltime approximation on relation to the variation of the wavefront parameters. By analysing the first<br>derivative of the Multifocusing Traveltime on relation to each one of the searched-for wavefront parameters, we<br>describe the behavior of the Common Reflection Surface. This result is important to indicate if exist a region of<br>the seismic data space where we could simultaneously do a three parameters optimization procedure.