Mabruk Reservoir in West Mabruk oil Field , (Sirt Basin, Libya)

Abstract

Abstract: The Sirt Basin in the north-central part of Libya is one of the youngest sedimentary basins on the African craton. Sedimentation was controlled by tectonic and eustatic influences, locally inducing high sedimentation rates with the distribution of the various lithologies being governed by ridge-and-trough paleotopography. The carbonate intervals of the Heira Formation which including the Mabruk Member, The upper Mabruk unit which represent the main reservoir producing oil in the Mabruk oil field in (Block C17), the main objective of this study was to evaluate the carbonate reservoir member by Petrophysical and geological analysis methods using Techlog and Petrel softwarefor five selected wells (B1-17 , B2-17 , B3-17 , B4-17, B5-17 ) .The upper Mabruk unit with gross thickness is ranging from 70 to 90 feet, while the net pay thickness ranging from 14 to 46 feet. The results reveled good reservoir quality content average porosity ranging from 14 to 23%, average permeability ranging from 19 to 309 MD, and average water saturation variations with some wells reached 34%, and increasing toward south reached 71% which located at the edge of oil water contact. the lateral facies evolution creates Petrophysical variations The heterogeneities is big impact in carbonate reservoir quality, although this study used only five wells with short distances between the wells but clear lateral variation encountered as in well B4-17 and B5-17 , heterogeneities can enhance physical properties such as permeability as it was in B4-17 and B5-17(19 and 191 md) .