Subsurface Structural Framework, Fault Modeling, and Petrophysical Analysis of Paleogene Carbonates in the Rajian Oilfield, Potwar Basin, Pakistan

Identifying the hydrocarbon potential zones in the structurally complex Potwar Basin, Pakistan is a challenging. The basin comprises of repeated thrust sheets and duplex structures indicating intense complication in structural interpretation, however such interpretations proved to be significant regarding hydrocarbon prospective. In current investigation, assimilation is made via seismic lines and conventional well logs of the Rajian oilfield of the Potwar Basin to delineate the comprehensive subsurface structures along with the assessment of petrophysical characteristics of the potential facies of the Paleogene carbonates. The time contour maps, and 3D faults interpreted on seismic sections were used as input for structural framework modeling showing the occurrence of repeated thrusts sheets, duplex structures in the region. In combination, the time and depth structural contour maps were assessed for stratigraphic trend of Paleogene strata i.e., Lockhart, Nammal, Sakessar and Chorgali Formation that showed deepening in south-west direction in comparison to shallow south-east. Hydrocarbon possessing perspective zones and reservoir properties of the Lockhart, Nammal, Sakesar and Chorgali formations of Rajian 01 well in the studied Potwar Basin were evaluated based on different conventional logs behavior including gamma ray, resistivity logs, density, sonic and neutron logs. The lithofacies were confirmed on petro-elastic cross plot that clearly discriminate the dolomite and limestone by quantitatively analyzing the values of cross plot. This investigation has resulted in an enhanced understanding of the structural complexities and stratigraphic heterogeneities that can influence the hydrocarbon exploration in the study area.