Petrophysical attributes of the middle zone of the Bahariya Formation as a producing reservoir using core analysis correlations and log evaluation, Abu Sennan area, Egypt

Abstract

Abstract A total of 78 sandstone core samples were obtained from the NES-2 well of the SWS field in the Abu Sennan area to assess the reservoir properties of the Middle Zone of the Bahariya Formation. It comprises carbonate, silt, and shale with sandstone interbeds, where the sandstone was targeted as it represents the main production zone in the studied area. The studied samples were subjected to porosity and permeability measurements, where the relationship between them showed the reservoir heterogeneity in terms of flow properties. Capillary pressure correlations displayed four hydraulic flow units with different performances within the studied samples in accordance with r35 parameter classification. The very permeable flow unit (megaport) constitutes 92% of the total flow capacity. Other petrophysical parameters such as apex, pore throat radii, reservoir quality index (RQI), and turbulence factor (β) were used to confirm the previous results and deeply evaluate the studied reservoir samples. Petrographically, the Middle Zone of the Bahariya Formation is represented by intercalations of siltstone, quartz arenite (the common facies), quartz wacky, and sandy siltstone facies from base to top. These microfacies represent the different petrophysical flow units. In terms of log evaluation, the middle zone of the Bahariya sandstone reservoir is characterized by a net pay thickness of about 6.9 m in the NES-2 well and marked by (Vsh = 0.05, ϕE = 0.24, and Sw = 0.4) as an oil producer. All the results were consistent and confirmed that the Middle Zone of the Bahariya Formation has excellent reservoir capabilities. Megaport flow units of the highest flow rate nature are predominant and nearly constitute the flow capacity, hence the reservoir may suffer some productivity loss under the turbulence flow conditions or the moving fines.