Rock typing based on hydraulic and electric flow units for reservoir characterization of Nubia Sandstone, southwest Sinai, Egypt

Abstract

The present work describes and evaluates the reservoir quality of the sandstone of the Nubia Formation at the Gebel Abu Hasswa outcrop in southwest Sinai, Egypt. Hydraulic flow unit (HFU) and electrical flow unit (EFU) concepts are implied to achieve this purpose. The Paleozoic section made up of four formations has been studied. The oldest is Araba Formation followed by Naqus formations (Nubia C and D) overlay by Abu Durba, Ahemir and Qiseib formations (Nubia B), where the Lower Cretaceous (Nubia A) is represented by the Malha Formation. The studied samples have been collected from Araba, Abu Durba, Ahemir and the Malha formations. The hydraulic flow unit (HFU) discrimination was carried out based on permeability and porosity relationship, whereas the electrical flow unit (EFU) differentiation was carried out based on the relationship between formation resistivity factor and porosity. Petrographic investigation of the studied thin sections illustrates that the studied samples are mainly quartz arenite. Important roles to enhance or reduce the pore size and/or pore throats controlling the reservoir petrophysical behavior are due to the diagenetic processes. The present study used the reservoir quality index (RQI) and Winland R35 as additional parameters applied to discriminate the HFUs. The study samples have five hydraulic flow units of different rock types, where the detected electrical flow units are only three. The differences between them are may be due to the cementation process with iron oxides that might act as pore filling, lining and pore bridging, sometimes bridges helping to decrease permeability without serious reduction in porosity. The reduction between the number of EFUs and HFUs comes from the effect of diagenesis processes which is responsible for a precipitation of different cement types such as different clay minerals and iron oxides.

Determining the petrophysical rock types utilizing the Fuzzy C-means Clustering technique and the concept of hydraulic flow units in the Asmari Formation, SW Iran

“…The selection of samples of the same pore attributes can be clustered in a similar hydraulic unit. The boundaries of rock genetic units a geologist represents may be useful for the reservoir engineer if they coincide with unprecedented changes in flow properties (El-Sayed et al, 2021;Ji et al, 2022;Ojo et al, 2021;Shalaby, 2021). The flow zone index method is the most commonly used method for determining rock Types.…”

“…According to the principles of hydraulic flow units, the distribution of the logarithm of the flow zone index in each hydraulic flow unit is the normal distribution. This method applies this principle and determines the number of hydraulic flow units (Al-Rbeawi and Kadhim, 2017;Alhashmi et al, 2016;Bhattacharya et al, 2016;El-Sayed et al, 2021;El Sharawy and Gaafar, 2016;Ismail et al, 2021;Kazemzadeh et al, 2013;Kianoush et al, 2022a;Kianoush et al, 2023a;Mirkamali et al, 2016;Roslin and Esterle, 2016;Salehi et al, 2015;Shakiba et al, 2015).…”

Determining the petrophysical rock types utilizing the Fuzzy C-means Clustering technique and the concept of hydraulic flow units

“…According to the principles of hydraulic flow units, the distribution of the logarithm of the flow zone index in each hydraulic flow unit is the normal distribution. This method applies this principle and determines the number of hydraulic flow units (Al-Rbeawi and Kadhim, 2017;Alhashmi et al, 2016;Bhattacharya et al, 2016;El-Sayed et al, 2021;El Sharawy and Gaafar, 2016;Ismail et al, 2021;Kazemzadeh et al, 2013;Kianoush et al, 2022a;Kianoush et al, 2023a;Mirkamali et al, 2016;Roslin and Esterle, 2016;Salehi et al, 2015;Shakiba et al, 2015). The result is four normal distributions representing four units of hydraulic current (Fig.…”

Determining the petrophysical rock types utilizing the Fuzzy C-means Clustering technique and the concept of hydraulic flow units

“…According to the principles of hydraulic flow units, the distribution of the logarithm of the flow zone index in each hydraulic flow unit is the normal distribution. This method applies this principle and determines the number of hydraulic flow units (Al-Rbeawi & Kadhim, 2017;Alhashmi et al, 2016;Bhattacharya et al, 2016;El-Sayed et al, 2021;El Sharawy & Gaafar, 2016;Ismail et al, 2021;Kazemzadeh et al, 2013;Kianoush et al, 2022a;Mirkamali et al, 2016;Roslin & Esterle, 2016;Salehi et al, 2015;Shakiba et al, 2015). The result is four normal distributions representing four units of hydraulic current (Fig.…”