Abstract: 3-D Design with DMO Modelling

D. L. Connelly, J. M. Galbraith

The seismic industry applies dip moveout (DMO) processing increasingly often to correct for the up-dip reflection point smear inherent in common midpoint (CMP) 3-D seismic surveys. DMO requires a complete reconstruction of a wave field by shifting and summing energy along source-receiver azimuths. To design 3-D surveys we require knowledge of the interaction between 3-D geometry and the effect of DMO on seismic data.

Black and Egan (1988) described a DMO filtering correction to correct a deformed flat event to uniformity for 2-D data with irregular geometry. Beasley (1993) proposed a technique to "count" the dips in dip-azimuth bins to assess the uniformity of offset-dip-azimuth distributions and a new set of attributes to consider during 3-D design. Beasley and Klotz (1992) also proposed the use of the flat-dip "count" multiplicity to correct for the amplitude variations appearing from variation in multiplicity on an implied signal and random noise model. Both techniques show great promise for future applications.

In this paper, we propose a more empirical, and therefore direct, method to determine the appropriateness of a particular 3-D geometry for DMO processing.

Given a dipping geologic event at a specified CMP position and at a specified time, we compute the input event times and OMP positions to model the DMO process. Thus, assuming that every CMP in the survey contains such a "pseudo" dipping event we produce the DMO response at every CMP position in the survey. Our process produces an estimate of the DMO response (and a possible DMO correction filter) for a particular survey geometry to a specified event (either flat or dipping).

AAPG Search and Discovery Article #90951©1996 AAPG International Conference and Exhibition, Caracas, Venezuela