Abstract

The offshore stringer sands that are north of Saudi Arabia contain significant oil and gas, but imaging these sands has been challenging. The sands and shales do not have a sufficient acoustic impedance contrast to appear in normal-incident seismic data, and the sand distribution is too erratic and complex to be predicted with subsurface stratigraphic techniques. Simultaneous offset inversion was used to separate sands from shales in the prestack domain based on elastic rock properties. The results have allowed us, for the first time, to target the sands via geosteering horizontal wells to maximize reservoir contact. Furthermore, the underlying massive main sand interval is better delineated and shows structural and stratigraphic events that were encountered during drilling, but never predicted. These results will have a significant impact on the overall drilling and production efficiency.

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