--> ABSTRACT: Geology and Habitat of Oil in Ras Budran Field, Gulf of Suez, Egypt, by L. R. Chowdhary and Said Taha; #91038 (2010)

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Geology and Habitat of Oil in Ras Budran Field, Gulf of Suez, Egypt

L. R. Chowdhary, Said Taha

Deminex (as operator for its partners, BP and Shell) discovered the Ras Budran oil field in 1978. Discovery well EE 85-1 was drilled in about 140 ft of water, 4 km off the Sinai coast of the Gulf of Suez. Appraisal drilling (EE 85-2, 3, and 4 wells) confirmed the presence of a major field with an estimated 700 million bbl oil in place. The field, developed from three wellhead platforms, went on production in April 1983. To date, 20 development wells have been drilled.

The Ras Budran structure at the deepest mappable seismic reflector, top Kareem (middle Miocene), is a broad northeast-southwest-trending anticlinal feature striking nearly at right angles to the main Gulf of Suez trend. At pre-Miocene producing horizons, the structure is complex and consists of a northeast-dipping flank (14-15°) broken into several blocks by faults and limited to the south and west by major bounding faults.

Oil is produced from three units of Nubian sandstone at a depth of 11,000 to 12,000 ft. The lower unit of Paleozoic age averages 10% porosity and up to 200 md in-situ permeability. The wells completed in this unit produce up to 2,000 BOPD. In contrast, the sands of the upper two units of Lower Cretaceous age have a 15-20% porosity and up to 700 md permeability. The wells completed in these units produce 6,000-8,000 BOPD.

The Ras Budran structure was primarily formed during the intra-Rudeis tectonic phase (lower Miocene). Migration of oil for accumulation in Ras Budran started late in the upper Miocene or Pliocene when the Santonian Brown Limestone and the Eocene Thebes Formation, the main source beds in the Gulf, reached the threshold of oil generation at a burial depth of about 10,000 ft (3,000 m). At these depths, the organic matter in the source beds have a transformation ratio (0.10 to 0.15), increased yields of C15 + soluble organic matter and C15 + saturated hydrocarbons, a vitrinite reflectance of 0.62%, and a TTI value of 15.

The migration of oil from adjoining synclines into Nubian sandstone reservoirs was controlled by faults, which acted as conduits for oil migration.

AAPG Search and Discovery Article #91038©1987 AAPG Annual Convention, Los Angeles, California, June 7-10, 1987.