STUDY OF VELOCITY FILTERING USING MULTICHANNEL ARRAY TECHNIQUES

Abstract

The developement of velocity/fan filters which makes it possible ~ to process a seismic record-section in such a way that all seismic events with dips in a given range are preserved with no alteration over a wide frequency range, while all seismic events with dips outside the specified range ar uniformly and severely attenuated) is discussed in this report. The implementation of the process is outlined. A general procedure for designing two-dimensional velocity filters, based on array filters derived originally for multichannel (multiple-input single--output) processing of the recordings of an array of sensors, is described. The mathematical expressions needed for implementation of the filters using the two- dimensional fast fourier transform are also included. A specific derivation of the velocity filters, based on a family of multichannel array filters, is described in detail. The software has been designed for the entire filtering process. The design of a spectrum analyzer and a pulse duration measuring instrument useful in certain measurements pertaining to pulses, is also presented.