How to Cite: Aljibouri, R. D., Al-Hakeem, N. S. A., & Nasser, M. E. (2022). 3D geological modeling for Yamama reservoir in Al-Nasiriyah oil field Southern Iraq. International Journal of Health Sciences, 6(S6), 8949–8962. https://doi.org/10.53730/ijhs.v6nS6.12376 International Journal of Health Sciences ISSN 2550-6978 E-ISSN 2550-696X © 2022. Manuscript submitted: 9 April 2022, Manuscript revised: 18 June 2022, Accepted for publication: 27 July 2022 8949 3D geological modeling for Yamama reservoir in Al-Nasiriyah oil field Southern Iraq Riyam Dhirar Aljibouri Department of Geology, College of Science, University of Baghdad, Baghdad, Iraq *Corresponding author email: reyamdirar22@gmail.com Naseem Shehab Ahmed Al-Hakeem Oil Exploration Company, Iraq Medhat E. Nasser Department of Geology, College of Science, University of Baghdad, Baghdad, Iraq Abstract---The geological modeling of an oil-bearing reservoir, which specifies the lithology and analyzes the petrophysical parameters of complex reservoir, its being created using Petrel software to construct reservoir models that describe and estimate porosity and water saturation distributions. 3D modeling of carbonate reservoirs has proven to be a highly effective technique for evaluate the economic benefit of the reservoir by estimating the formation petrophysical properties and calculating the oil reserves. The study aims constructed on evaluated Yamama formation in Four drilling wells (Nasiriyah-1, Nasiriyah-3, Nasiriyah-4, and Nasiriyah-5) entering the Yamama Formation of the Al-Nasiriyah field. In Al-Nasiriyah Oil field, and within the Lower Cretaceous Stratigraphic Column in the south of Iraq, the Yamama Formation is one of the most important reservoirs that deposited into shallow marine habitats throughout the (Valanginian- Early Hauterivian) period, that made up of reservoir and impermeable barrier units in the Al-Nasiriyah field, Yamama Reservoir units are divided into three reservoir units (YA, YB, and YC), with the YB reservoir unit subdivided into (YB1, YB2, and YB3) subunits. The main reservoir units are separated by four sharp impermeable barriers represented by (B1, B2, B3, and B4). Generally, the 3D Geological modeling concluded that the YB reservoir unit represents the best petrophysical properties reservoir unit represented by (highest porosity, lowest water saturation) with an average thickness of about (81.5-124.5 m) in most studied wells, while the YC reservoir is moderately Good after YB unit more than YA represents the lowest petrophysical Unit, where unit YB and YC represented Oil bearing zones that product of Oil percentage strong oil with gas in some intervals.