Reservoir Geology and Hydrocarbon Occurrence in the Alam El Buieb Formation, Western Desert, Egypt

Fred Wehr, Warren Barnes, Brian Bullock, Hesham Ghaffar, Stephen Grant, et al.
¹Khalda Petroleum Co, Cairo, Egypt

The Alam El Buieb Formation (AEB) is a major oil and gas reservoir in the western desert of Egypt. In the Khalda concession it has produced over 100 million barrels of oil and 100 BCF of gas since 1985, and is currently producing over 20,000 BOPD.
The AEB consists of up to several thousand feet of a mixed clastic-carbonate succession, dominated by stacked fluvial sandstones and punctuated by transgressive marine shales and carbonates. Hydrocarbons are found trapped in isolated fluvial or incised valley sandstones immediately beneath the marine intervals. In fields with larger closure heights, the oil column can extend into amalgamated fluvial sands. The Isolated channel sands produce via pressure depletion with little or no aquifer support, whereas amalgamated fluvial sands show strong aquifer support with no pressure depletion. Production rates are generally good, typically 1500-3000 barrels of fluid per day.
Early production from the AEB was from large four-way closures with hydrocarbons trapped in both channelized and amalgamated reservoirs. More recent exploration and development has focused on smaller three-way, fault dependent closures where trap and reservoir risk are higher. Seismic data is not sufficient to resolve reservoir-scale geology, so sand prediction relies on careful mapping and log-based tools.
Despite these challenges, it has been possible to nearly double AEB oil production over the past six years through a combination of aggressive drilling, fracture stimulation and targeted waterflooding. It continues to be a major target for exploration and development drilling in the Khalda concession.

AAPG Search and Discovery Article #90072 © 2007 AAPG and AAPG European Region Conference, Athens, Greece