The Abu Gharadig and Faiyum basins are areas which have some of the greatest hydrocarbon potential in the Western Desert of Egypt. Several extensive cycles of marine transgression and regression occurred in these territories through geologic time. The depositional cycles combined with at least 3 tectonic cycles--(1) the Hercynian orogeny at the end of the Paleozoic, (2) from Late Jurassic to early Tertiary, and (3) from Late Cretaceous to middle Tertiary--resulted in a highly deformed, thick sedimentary sequence. This organic-rich Jurassic-Upper Cretaceous-lower Tertiary sequence in large areas of these basins was subjected to enough heat and depth to generate hydrocarbons. It is evident from recent discoveries that these source rocks generated large amounts of high-quali y oil and gas.

The Abu Gharadig and Faiyum basins are separated structurally by a major ridge. Both basins are bounded on the north by another major ridge associated with Cretaceous and Tertiary faulting. A major platform with thin sedimentary cover forms the southern boundary.

The hydrocarbon potential exists in cyclic sequences of sandstone, shale, and carbonate, having moderate porosities and permeabilities. An important hydrologic phenomenon prevails in major parts of the basins; fresh water has flushed the early Cenomanian and older reservoirs. The eastern part of the Faiyum basin, the southern platform, the Kattaniya high, and the southern and western rims of the Abu Gharadig basin are completely flushed, leaving little chance for hydrocarbon preservation in these localities.

Exploration efforts should be concentrated on deep structures close to the main depocenters and inside or very close to the 150°F (65°C) geothermal contour. Contemporaneous structures on the northern rims of the basins should have high potential, resulting from migration of hydrocarbons from the south across major faults. The Jurassic in the northeastern part of the Abu Gharadig basin may provide good hydrocarbon potential. The lower Tertiary sequence present in the troughs also may have large amounts of oil entrapped in situ or resulting in short-distance migration to the northern structures or to the Late Cretaceous-early Tertiary Syrian arc traps.