Purpose. The purpose of this study is to investigate the clay content and petrophysical characteristics of the Rutbah Formation
in the Sijan Field and their impact on production. This involves analyzing various borehole measurements to assess
reser-voir quality and predict fluid flow behaviour. Additionally, the study aims to compare wells in the Sejan field to show the
differences in petrophysical properties, especially hydrocarbon saturation in the Rutbah sand formation.
Methods. Methods include gamma-ray measurements to determine rock lithology and calculate shale volume. Permeability
is analyzed using equations relating permeability and porosity. Porosity determination involves acoustic, neutron, and density
porosity measurements. The Archie equation was used to calculate water and hydrocarbon saturations.
Findings. Gamma-ray measurements delineated the Rutbah Formation’s upper and lower sections. The upper Rutbah
exhibits higher gamma-ray anomalies and shale volumes compared to the lower Rutbah. Shale in the upper Rutbah leads to
ineffective porosity, while the lower Rutbah, dominated by sandstone with minimal shale, shows higher permeability suitable
for hydrocarbon production.
Originality. The study highlights the significance of well logging data as a cost-effective alternative to traditional methods
for estimating clay content and assessing reservoir quality in real-time. It contributes to literature by investigating influence of
clay content variations on reservoir properties, enhancing reservoir characterization and production forecasting.
Practical implications. The study provides insights for oil exploration and production strategies in the Rutbah Formation
within the Euphrates Graben region. Understanding the distribution of clay minerals and their effects on reservoir properties
can guide exploration and development efforts, optimizing hydrocarbon recovery.