The Reservoir potential of Middle Jurassic sedimentary deposits in the Imhotep Field, Matruh Basin, North-Western Egypt

Abstract

This study examines the reservoir potential of the Middle Jurassic Khatatba Formation in the significant gas producer Imhotep Field, Matruh Basin, northwestern Egypt. The Upper Safa member sandstones of Khatatba Fm are characterized by low-quality, confined sandstone reservoirs. Yet, the Lower Safa member sandstones show better gas reservoir quality and exhibit remarkable decreases in shale volumes, including kaolinite. There is about a 30 m gross thickness, a 10 m net effective pay, about 6 % average effective porosity, 21% mD permeability, 12% shale volume, 24% water saturation and ~77% average hydrocarbon saturation. The deeply seated Lower Safa sandstone reservoirs in the Imhotep W-1X well are not suitable for gas production because they show a high decline in production and pressure tests. Therefore, they require high pressure to produce gas and condensates, which is probably not economically feasible. Moreover, geomechanical results indicate that the Lower Safa member is a brittle reservoir with better drilling capabilities than the more ductile Upper Safa member. Because of the vertical facies change and sandstone low-permeability in the Khatatba Fm, the quality of the reservoir is seen as the biggest risk that was tested in the field. In general, the Khatatba Fm in the Imhotep Field is a better reservoir because it is mostly made up of coarse, organically poor clastic deposits in the Imhotep W-1X well area. More studies based on multi-approach analysis are needed to fully examine the regional reservoir potential of the Khataba Fm in the Matruh Basin.