Data processing and computer techniques for marine seismic interpretation

Abstract

This work is divided into two sections, the first containing results and interpretations from marine seismic reflection profiling performed by Durham University (1972) in a region to the north of the Faeroe Islands, and the second containing theories for the removal of multiple reflection effects from marine seismic records by means of digital data processing techniques. The seismic profiling investigations were carried out to ascertain the geological structure causing the gravity 'low' north of the Faeroes which had previously been proposed by Bott, Browitt and Stacey (1971) to be caused by an infilled valley. Results from the 1972 survey shows that this infilled valley has a limited aerial extent containing relatively large basement undulations. Further work was carried out to obtain information about the sedimentary' sequencies and to try and correlate these with sediments in surrounding regions where data had been obtained by previous workers. The profiling work (1972) indicated three major sequencies within the sedimentary column with an overall thickening of sediments away from the uplifted areas of the Iceland - Faeroe Ridge and Faeroe Islands. The data processing section deals principally with the removal of multiple reflections from marine seismic records. An introduction is given to the basic concepts involved throughout this work, and includes a description of noise theory and types of multiple reflections encountered in marine seismic profiling. Some previous methods for multiple elimination are improved upon and then two new techniques are developed, applied to seismic sections, and finally a comparison made between the techniques used. All programs are written in FORTRAN IV for use on the IBM 360 computer, and for displaying purposes, facilities available with the Durham IBM 1130 plotting system were used.