LIMITATIONS OF THE REFLECTION SEISMIC METHOD; LESSONS FROM COMPUTER SIMULATIONS

Abstract

Piece‐wise local linearity of the subsurface reflectors and uniqueness of primary reflection travel path between particular source‐receiver pairs are two of the fundamental assumptions of multiple ground coverage reflection seismic techniques as currently employed. Some recent developments in seismic exploration which spring from the progress made in velocity determination techniques violate these fundamental assumptions with potentially serious consequences such as spurious geometries after migration and unrealistic interval velocities. In this paper we apply analytic techniques and computer simulation to linear and nonlinear subsurface models in order to obtain better definitions of the limitations of the reflection seismic method. The resulting lessons are of immediate practical value in seismic interpretation and clarify a variety of commonly occurring but puzzling situations such as phantom faults, incomplete contacts and segmented reflectors at unconformities, and apparent reversal of dip. In its basic approach this work has much in common with the generation and study of synthetic seismograms. Examination of the groundwork of the seismic method provides a firm base for extending its use.