An undrilled and structurally inverted half graben basin has been identified on the North Eastern margin of the Gulf of Aden in Block 52, Offshore Southern Oman. This block (Fig. 1) was awarded to Circle Oil in September 2005 and originally covered an area of 90,760 sq km. The known stratigraphy of the area ranges in age from Precambrian to Tertiary, based on onshore outcrops, offshore well penetrations, and seismic interpretation. Much of the Paleozoic is absent in the offshore wells. The identified principal reservoir intervals are Paleogene, Hadhramaut, and Upper Cretaceous Aruma Group carbonates (Fig....