The Red Sea/Gulf of Aden Hydrocarbon Potential Reassessment

BEYDOUN, Z. R., American University of Beirut, c/o Marathon Petroleum, London, United Kingdom

Samples from most of the 85 exploration wells drilled in the Red Sea and Gulf of Aden, made available to the UNDP/World Bank Red Sea/Gulf of Aden Regional Hydrocarbon Study Project by the participating states were examined for biostratigraphy and source rock geochemistry. Simultaneously, seismic lines covering much of the shallow offshore area were interpreted, and regionally significant levels mapped and isopached using regional gravity and magnetic input. Enhancement of selected regional key lines by reprocessing assisted in mapping the broad configurations of basement structure in more precise resolution of prospective sediment packages.

Major tectonic elements segment both basins, but in the Gulf of Aden this is less evident as the drift stage is more advanced; additionally, the Red Sea exhibits asymmetry in crustal composition. All this has influenced the location and development of major sediment depocenters and delta fans, whereas haiokinesis has also further influenced source kitchen development in Red Sea.

Major Neogeon syn-rift and post-rift (Miocene-Pliocene) lithostratigraphic units are correlatable from the petroliferous Gulf of Suez over the Red Sea; pre-rift (Paleogene and older) and syn-rift/post-rift (Oligocene-Miocene/Pliocene) units correlate well across the Gulf of Aden, with evidence of progressive transgression from the Gulf of Aden (middle Oligocene) to the southern Red Sea (upper Oligocene) to the northern Red Sea/Gulf of Suez (lower Miocene).

Source-rich intervals are present in the mega-sequence of the pre-rift and syn/post-rift packages. Three undeveloped gas and condensate discoveries and a gas blowout plus numerous oil seepages in the Red Sea, and a black oil discovery in the Gulf of Aden are testimony to hydrocarbon generation and entrapment. Although a higher geothermal gradient is present in the southern Red Sea, modeling of the entire basin (rather than in segments) indicates that, contrary to conventional wisdom, the region is neither too hot nor all gas prone, but it possesses the geological parameters conducive to the generation, expulsion, and trapping of significant amounts of oil and gas.

AAPG Search and Discovery Article #91007© 1991 AAPG International Conference, London, England, September 29-October 2, 1991 (2009)