Petroleum geology and potential hydrocarbon plays in the Gulf of Suez rift basin, Egypt

Abstract The Gulf of Suez in Egypt has a north-northwest-south-southeast orientation and is located at the junction of the African and Arabian plates where it separates the northeast African continent from the Sinai Peninsula. It has excellent hydrocarbon potential, with the prospective sedimentary basin area measuring approximately 19,000 km2, and it is considered as the most prolific oil province rift basin in Africa and the Middle East. This basin contains more than 80 oil fields, with reserves ranging from 1350 to less than 1 million bbl, in reservoirs of Precambrian to Quaternary age. The lithostratigraphic units in the Gulf of Suez can be subdivided into three megasequences: a prerift succession (pre-Miocene or Paleozoic-Eocene), a synrift succession (Oligocene-Miocene), and a postrift succession (post-Miocene or Pliocene-Holocene). These units vary in lithology, thickness, areal distribution, depositional environment, and hydrocarbon importance. Geological and geophysical data show that the northern and central Gulf of Suez consist of several narrow, elongated depositional troughs, whereas the southern part is dominated by a tilt-block terrane, containing numerous offset linear highs. Major prerift and synrift source rocks have potential to yield oil and/or gas and are mature enough in the deep kitchens to generate hydrocarbons. Geochemical parameters, sterane distribution, and biomarker correlations are consistent with oils generated from marine source rocks. Oils in the Gulf of Suez were sourced from potential source rock intervals in the prerift succession that are typically oil prone (type I), and in places oil and gas prone (type II), or are composites of more than one type (multiple types I, II, or III for oil prone, oil and gas prone, or gas prone, respectively). The reservoirs can be classified into prerift reservoirs, such as the Precambrian granitic rocks, Paleozoic-Cretaceous Nubian sandstones, Upper Cretaceous Nezzazat sandstones and the fractured Eocene Thebes limestone; and synrift reservoirs, such the Miocene sandstones and carbonates of the Nukhul, Rudeis, Kareem, and Belayim formations and the sandstones of South Gharib, Zeit, and post-Zeit. The majority of oil fields in the region incorporate multiple productive reservoirs. Miocene evaporites are the ultimate hydrocarbon seals, whereas the shale and dense limestones of the prerift and the synrift stratigraphic units are the primary seals. Structural, stratigraphic, and combination traps are encountered in the study area. The Gulf of Suez is the most prolific and prospective oil province in Egypt, and any open acreage, or relinquished area, will be of great interest to the oil industry.