Assessment of the petrophysical properties and hydrocarbon potential of the Lower Miocene Nukhul Formation in the Abu Rudeis-Sidri Field, Gulf of Suez Basin, Egypt

Abstract

Lower Miocene rift sediments of the Nukhul Formation are one of the prominent hydrocarbon producers in the Gulf of Suez basin. In this study, we focused on the oil producing Nukhul sandstones of the Abu Rudeis-Sidri Field, located in the east central Gulf of Suez. Nukhul Formation is characterized by the prominent low amplitude seismic reflectors and represents the youngest identified reflector (Lower Miocene) in the study area. Petrophysical assessment was carried out using wireline logs to infer the reservoir characteristics. The Nukhul sandstone reservoir exhibits lower shale volume (< 0.1 dec dominantly), 0.07–0.16 dec total porosity and effective porosity up to 0.13 dec within the Nukhul sandstone interval. Bulk density-neutron porosity cross plot infers primarily sandstone matrix with the influence of carbonates, which characterizes the studied reservoir as calcareous sandstones. Spectral gamma ray data indicates montmorillonite as the principal clay phase along with minor kaolinite and illite. The calculated water saturation of the reservoir zone in the three productive wells ranges between 0.17 and 0.34 dec (i.e., the hydrocarbon saturation equals 0.66–0.87 dec). A small range of bulk volume of water (0.011–0.03 dec) indicates superior quality of the hydrocarbon-bearing sandstone intervals. Absence of productive sands in one of the studied wells, drilled in the hanging wall implied structural control on hydrocarbon accumulation in the study area. This study provides crucial insights regarding the quantitative petrophysical characteristics, reservoir quality distribution and hydrocarbon potential of the Lower Miocene Nukhul clastic reservoir.