3-D Physical Seismic Modeling Study of a Lower Cretaceous Channel in Southern Alberta

Kelly Dale Hrabi

ABSTRACT

Channel-sands of the Lower Cretaceous Glauconitic Formation in southern Alberta are important petroleum reservoirs. They have subtle seismic characteristics which can often be confused with shale-filled channels. Acoustic 2-D and 3-D physical seismic modeling over a Glauconitic channel was undertaken to gain insight into its seismic signature. Physical modeling and 3-D survey design conclude that fold, offset and azimuth distribution are significant for producing a high quality image of the channel structure. Three surveys, a 2-D, zero-offset 3-D and full-offset 3-D were acquired and processed. All three surveys produce a high quality image of the channel with the accompanying bars and displayed the velocity pull-up anomaly on the Mississippian event but only the full-offset 3-D survey was able to image the velocity pull-down on the Mississippian event. From this modeling study it was concluded that full-offset 3-D surveys are important for distinguishing a sand-filled channel from a shale-filled channel.

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