Egypt Exploration Society

ABSTRACT The Wadi Rayan oil field has experienced inconsistent production. This stems from lateral and vertical heterogeneities within the sandstone reservoirs, which profoundly impact hydrocarbon flow. A comprehensive multiscale study integrating sequence stratigraphy, seismic interpretation, and petrographic analysis was conducted to characterise the reservoir system. Our results reveal a complex, tidally‐dominated estuarine system deposited during the Cenomanian on a low‐gradient shelf. Crucially, reservoir quality is facies‐controlled, with high‐energy channel sands preserving good porosity (0.15–0.28) despite silica cementation, whereas moderate‐energy tidal bars suffer significant porosity reduction from calcite cementation. Structurally, the main field closure is a NE‐asymmetrical anticline bounded by faults. We constructed a 3D static model using detailed facies and property distributions, estimating cumulative stock tank original oil in place of 16.33 MMSTB across three reservoir intervals. The model definitively identified a critical stratigraphic barrier—composed of low‐permeability shelf shale and carbonate facies—that compartmentalises the reservoir and explains the presence of dry wells (e.g., WR‐2X and WR S‐1X) at structural highs. This finding challenges the notion that structure alone controls entrapment, demonstrating instead that stratigraphic complexity can override the structural template. We consequently propose drilling two appraisal wells to further evaluate future planning. This integrated approach conclusively links dry wells to specific stratigraphic complexities, enhancing reservoir understanding and providing a predictive framework for improving recovery in similar geological settings.

Ten years is a long time in geophysics. In the early days of 3D seismic surveys, in the 1980s say, it might have taken two years to acquire and process a 3D survey, and many business decisions simply could not wait that long. By the mid-1990s, our seismic contractors had done a wonderful job of making 3D seismic faster and cheaper while making it better—truly a “class act.” Thanks to them, the overwhelming technical advantages of 3D are in routine use in almost every possible application today.

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