October field, the third largest oil field in Egypt, produced over 420 million bbl of oil from its discovery in 1977 until January 1991. It is the northernmost giant oil field in the Gulf of Suez rift basin. Forty-five wells from eight platforms in approximately 58 m (190 ft) of water drain over 3703 ha (9150 ac) of the October producing trend. Recent reservoir discoveries demonstrate the viability of continuing exploration along this oil-rich trend.

This structurally trapped field is a complex of rotated fault blocks typical of rift basins worldwide. A northwest-trending normal fault with a throw of approximately 1220 m (4000 ft) has trapped the largest of several oil accumulations, which has a 333-m (1092-ft) oil column on the upthrown eastern side. Severe seismic multiple problems resulting from thick Miocene evaporites restrict definition of the highly productive prerift section. These same evaporites serve as the ultimate seal throughout the Gulf of Suez. Approximately 95% of field reserves are within Carboniferous to Lower Cretaceous massive Nubia Sandstones, with remaining reserves in more lenticular Upper Cretaceous sands, basal Miocene rift-fill Nukhul Formation clastics, and the Asl Member of the Miocene Upper Rudeis For ation.

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Several distinct reservoir accumulations exist, with the deepest and most significant original oil-water contact at -3558 m (-11,670 ft) subsea. October field oil gravities range from 14 to 39° API. The main source rock unit for the field is postulated to be the Campanian Brown Limestone Member of the Sudr Formation. Typical reservoir parameters for the Nubia Formation are: porosity, 17%; permeability, 236 md; and net pay thickness, 137 m (450 ft). The expected recovery factor is 45%. A field-wide reservoir study is currently in progress to address reservoir management of the October area. GUPCO (the joint operating company for Amoco Production Company and the Egyptian General Petroleum Company) operates October field, which from all reservoirs produced approximately 170,000 BOPD t the beginning of 1991.