Mike Bahorich

3-D seismic discontinuity for faults and stratigraphic features: The coherence cube

Seismic data are usually acquired and processed for imaging reflections. This paper describes a method of processing seismic data for imaging discontinuities (e.g., faults and stratigraphic features). One application of this nontraditional process is a 3-D volume, or cube, of coherence coefficients within which faults are revealed as numerically separated surfaces. Figure 1 compares a traditional 3-D reflection amplitude time slice with the results of the new method. To our knowledge, this is the first published method of revealing fault surfaces within a 3-D volume for which no fault reflections have been recorded.

3-D Seismic Discontinuity For Faults And Stratigraphic Features: The Coherence Cube

Seismic data are usually acquired and processed for imaging reflections. This paper describes a method of processing seismic data for imaging discontinuities (e.g., faults and stratigraphic features). One application of this nontraditional process is a 3-D volume, or cube, of coherence coefficients within which faults are revealed as numerically separated surfaces. Figure 1 compares a traditional 3-D reflection amplitude time slice with the results of the new method. To our knowledge, this is the first published method of revealing fault surfaces within a 3-D volume for which no fault reflections have been recorded.

3-D Seismic Coherency And the Imaging of Sedimentological Features

A coherency time slice at 1250 ms, corresponding to a Pleistocene surface at approximately 4000 ft. below sea level, from the South Marsh Island area of the Gulf of Mexico displays a complex system of channels which in part are similar to the channel system of the present Mississippi Delta. A comparison of Pleistocene channel geometries with the modem delta suggests the presence of a main Mississippi trunk channel and its associated distributary channels. Apparent lateral accretion and point bar development are observed on the coherency slice where a distributary channel crosses a fault. This interpretation is confirmed using seismic and log data. Complex linear zones of relatively low coherency were also observed on the coherency slice. Seismic and log data from these areas suggest these features are reworked deltaic sands overlying a complex system of channels.

3‐D seismic coherency techniques applied to the identification and delineation of slump features

3-D seismic coherency techniques and associated calculations of dip and azimuth of the coherent seismic reflections have been used successfully to aid in the identification and delineation of slump blocks with both high and low seismic amplitudes within a submarine canyon in the South Marsh Island area of the Gulf of Mexico. Block faces with low amplitude, but relatively high coherence, which are not evident on standard seismic time slices, can be seen on coherency time slices and dip/azimuth plots. These slump blocks produce a distinctive mottled pattern on coherency time slices and correspond to areas of high dip and varied azimuth on dip/azimuth plots. Similar coherency and dip/azimuth patterns are found elsewhere in the world, associated with slumping in areas of faulting, dewatering, and mass wasting.

Stratigraphic and structural interpretation with 3‐D coherence

3-D seismic coherence is useful for identifying faults, stratigraphic features and the relationship between them (Bahorich, and Farmer, 1994). This paper documents the use of this technology in three basins; the Gulf of Mexico, the North Sea, and the Ardmore Basin of Oklahoma.

SEG Las Vegas 2008

One of the most important functions of a professional society is honoring those who have made significant contributions to the profession and to science. This function is implicit in SEGs constitutional objective “to promote the science of geophysics, especially as it relates to exploration and research, to foster the common scientific interests of geophysicists, and to maintain a high professional standard among its members.”