Geological and Petrophysical Characterization of the Lower Senonian Matulla Formation in Southern and Central Gulf of Suez, Egypt

The Lower Senonian Matulla Formation is well developed in the southern and central Gulf of Suez. It can be subdivided into three depositional units (M1–M3). An obvious unconformity separated the middle unit (M2) from the upper unit (M3). The three units are corresponding to a second-order depositional sequence. This sequence consists of two systems tracts; the lower lowstand systems tract consists of slope fan, followed by a prograding complex. An erosion surface separated the lower from the upper transgressive systems tract. The Matulla Formation is mostly composed of sandstones and pelagic sediment intercalations. Such intercalations show obvious facies change throughout the study area, causing further subdivision of the Matulla Formation into seven rock types (RT1–RT7). The petrophysical reservoir evaluation has been achieved via determination of the effective porosity, permeability, shale content, water saturation and net-pay thickness from the environmentally corrected well log data. It indicates that the Matulla Formation can be considered as a good reservoir quality especially in its lower unit and sometimes in its middle unit as well. The available core data indicate a lithological heterogeneity of the studied Matulla Formation. Lithologically, it can be subdivided into four petrophysical and lithological facies; namely, they are sandstones, ferruginous sandstones, argillaceous sandstones and limestones. The best petrophysical properties were assigned for the ferruginous sandstones with good to excellent porosity, very good to excellent permeability, and poor to fair flow zone indicator.