Foredeep Prospectivity in a Compressional Tectonic Regime, the Pabdeh Group, Ras Al Khaimah

The Pabdeh Group of Tertiary Paleocene to Oligocene age was deposited in a foredeep basin created by an obducted compressional thrust front that extends from Northwestern Oman into the Northern Emirates. The unit is represented by marls interbedded by thin calciturbidites and sandstones, the latter of which become more frequent in the Oligocene. The maximum thickness of the Pabdeh in the basin depocentre is ~3.5 km. The hydrocarbon play is proven in the Hamidiyah oilfield, located in Ajman, and is being pursued in Ras Al Khaimah utilizing recently acquired 3D seismic and legacy well data. Modern Play Based Exploration techniques including interpretation and integration of 3D seismic, Full Tensor Gravity (FTG), local well information, integration of biostratigraphic data, and geochemical analysis of source rocks was used to delineate the Pabdeh play area. The identification of delta fronts, channels, and basinal fans on seismic was linked to the complex interplay between tectonic and eustatic base level changes. Seismic morphologies were then supplemented by seismic amplitude analyses, and outcrop studies in the Emirate of Ras Al Khaimah (RAK). Ductile compressional folding due to closure of the Neo Tethys Basin is proven to have also effected sedimentation patterns with ponded fans also developing on the paleo-shelf. The Pabdeh Group is a thick monotonous unit that requires high resolution biostratigraphy with seismic guided sequence stratigraphy, to identify mappable units and unconformities across the foredeep basin. The Middle Eocene Pabdeh Fm. Is the primary reservoir target in the Hamidiyah Field. Pabdeh calciturbidites represent lowstand sedimentation basinward of major incisions. These calciturbidites were deposited as debris flows originating from deltas near the thrust front. Submarine channels were cut into the shelf edge along the compressional thrusting front (in the present near offshore of RAK), and basinal fans can be observed in the present-day offshore 3D seismic. The calciturbidite facies has been identified in several wells with clear hydrocarbon shows and successful tests. Structural traps can be defined in tight ductile folds with a N-S trend, along with potential for stratigraphic traps. Main risk factors are around reservoir effectiveness and clearly defined migration pathways. For the first time the detailed sequence stratigraphy of the Pabdeh Group has been used to determine prospectivity in RAK and is now being expanded across the Northern Emirates using modern 3D seismic and Play Based Exploration (PBE) techniques.