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Pitfalls in Seismic Exploration for Trenton/Black River Reservoirs in the Michigan Basin

Matthew A. Johnston

West Bay Exploration Company, Traverse City, MI 49684

Seismic exploration for Trenton/Black River hydrocarbon reservoirs in the Michigan Basin may be complicated by shallow ray path anomalies that may affect the reflection character of the Trenton/Black River interval. Lateral changes in glacial drift thickness and/or composition may cause both false structures and false apparent stratigraphic variations on seismic sections. Using short source and geophone arrays in seismic data acquisition may improve shallow resolution and therefore aid in identifying anomalous drift features that may be affecting the deeper data. In addition, comparing seismic sections at various stages of processing may help identify potential problem areas in terms of drift statics corrections. Specifically, comparing an elevation-only statics version of a seismic section with its corresponding refraction statics version can identify potential false structures.

The Silurian Salina Group is another potential source of problems in exploring for Trenton/Black River reservoirs. The interbedded salt/carbonate facies of the Salina Group produce strong interbed multiples which can significantly contaminate the seismic data below this interval. These interbed multiples arise due to the very high velocity and density contrasts between the salts and carbonates which produce very high acoustic impedance contrasts. These multiples may be recognized by careful modeling with synthetic seismograms using both velocity and density information. These multiples remain a significant problem in the salt portion of the Michigan basin.

AAPG Search and Discovery Article #90059©2006 AAPG Eastern Section Meeting, Buffalo, New York