Geological and Petrophysical Characterization of the Triassic Sedimentary Succession of Benkahla Field in the Oued Mya Basin, Central Sahara Platform, Algeria

ABSTRACT The Triassic clastic sequence in the Oued Mya Basin is one of the most prolific ones in the central Sahara platform of Algeria. However, no detailed petrophysical study has been published on the Triassic sequence in the Oued Mya Basin. Therefore, this study aims to examine the structural setting and petrophysical properties of the Triassic sequence in Benkahla Field within the Oued Mya Basin. A set of well log data, including the gamma‐ray, density, neutron, and resistivity logs, was available from 21 wells to study the petrophysical properties of the Triassic sequence in Benkahla Field to estimate the total and effective porosity, shale volume, water saturation, and the net‐pay thickness. In addition to the well log data, a set of core data was available, including density, porosity, and permeability that have been used to calibrate the well log data and estimate the reservoir quality parameters. This helped in defining the prolific zones in the Triassic reservoir. With the present data, some X – Y plots, iso‐parametric maps, and facies models were prepared. The prepared plots, maps, and models indicated that the Benkahla Field is primarily controlled by a complex geometry configured by a set of NE–SW faults, along with another subsidiary set oriented N–S. From the well log data, the average values of porosity, water saturation, shale volume, and net‐pay thickness of this sequence in the various wells are promising. Considering the core data, it is achieved that the Triassic sequence can be divided into seven petrophysical static rock types (PSRTs), with the best reservoir quality measured for the PSRT1. The unusually high flow zone indicator (FZI), effective pore radius of Winland ( R 35 ), and permeability ( k ) values, along with relatively fair porosity values, indicate the presence of a microfracture system that has improved the reservoir quality of this rock type. On the other hand, the PSRT7 is characterized by the lowest reservoir quality. The applied workflow for this case study is applicable to other highly fractured clastic reservoirs in North Africa and elsewhere that are characterized by unusually high FZI and R 35 .