Mohammed Farfour, Wang Jung Yoon and Youngeun Jo
Keywords: Glauconitic channel, spectral decomposition, short time widow Fourier transform.
Abstract: In this study, we analyzed 3-D seismic and well-log data from the Blackfoot Field, Strathmore, Alberta, Canada, using seismic inversion and spectral decomposition to resolve the channel-fill Glauconitic sand. The Glauconitic sand is of Early Cretaceous age and forms the oil-bearing reservoir in this field. The sandy channel fill basically is characterized by low acoustic impedance whereas shale plugged channels are characterized by high acoustic impedance. However, the presence of non producing shale zones with low impedance similar to that of the oil sand made the acoustic impedance not an unambiguous diagnostic of hydrocarbon bearing sand. Additionally, regional geology wells producing from shallower zone show also a similar response to that of the sandy channel, thus, the need for another indicator to remove this ambiguity became a necessity. Spectral decomposition has been selected to play this role. To achieve this objective we relied on the fact that this attribute has proven to have the potential to selectively illuminate formations at their tuning frequency which can be different for hydrocarbon and non hydrocarbon saturated rocks. Interestingly, Short Window Fourier Transform workflow could successfully image the channel\'s stratigraphic features and differentiate shale from sand. Furthermore, the attribute could discriminate the regional geology from oil sand-fill channel in dry wells located in relatively low impedance area where the differentiation using P-impedance was ambiguous.
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