Petrophysical Evaluation of the Zubair Formation’s Main Pay Zone Using Conventional and NMR Log Data: Insights from the North Rumaila Field, Southern Iraq

Abstract

Listen

Translate article

This study investigates the calculation of petrophysical properties using both conventional logging tools and Nuclear Magnetic Resonance logs for the main pay zone of the Zubair Formation, Recognized as one of the most significant hydrocarbon-producing formations in the North Rumaila Field, located in southern Iraq, the main pay zone is categorized into three permeable units (AB, DJ, and LN) and two impermeable isolated zones (C and K) based on log responses. The petrophysical analysis of these zones indicates that the shale volume increases toward the northern part of the field due to the depositional environment. Effective porosity values across these zones range from fair to good; however, some wells in the AB layer exhibit excellent porosity, notably wells X-7, X-62, X-83, and X-110. Additionally, hydrocarbon saturation levels remain consistently high in the AB and DJ layers, whereas certain wells in the LN layer display lower saturation values, particularly wells X-85, X-78, X-63, X-110, X-84, X-19, and X-115. Furthermore, permeability values were calculated using the KSDR equation based on Nuclear Magnetic Resonance logs that span from good to very good, except well X-115, demonstrating excellent permeability in the AB layer.