Syn-Rift Lowstand Wedges: An Emerging Stratigraphic Play in the Suez Rift, Egypt

By

 David A. Pivnik¹, Jay Thorseth¹, Donald Easley¹, Jasper Peijs¹, James W. Stewart¹

(1) BP, Houston, TX

 The dominant play type in the Suez Rift, Egypt, is the upthrown, 3-way closure on footwalls of major normal-fault bounded structural blocks, with reservoirs in pre- and syn-rift rocks. To date, more than 90% of the ~9 billion barrels of oil that have been discovered in the basin have come from these types of traps. The remaining reserves are from a few downthrown syn-rift reservoirs located in the immediate hanging walls of major structural blocks, and even fewer traps with stratigraphic components.

What has remained unexplored is the potential for large, syn-rift depositional features preserved in the centers of grabens between major blocks. We show examples of syn-rift, lowstand, basin-floor fan deposits from the Gulf of Suez portion of the rift. These deposits are not controlled by well penetrations, but are predicted using the syn-rift stratigraphy in wells on surrounding horsts. We use biostratigraphically controlled syn-rift sequences and their bounding unconformities to predict the location, both temporally and spatially, of these basin-center deposits. We also use seismic-derived isopachs and seismic-stratigraphic interpretations to locate and map these features. However, due to the poor quality of seismic data caused by multiples generated from overlying middle Miocene evaporitic rocks, these depositional features are difficult to image and accurately map. Thus the lowstand wedge remains a high risk play type.