Petrophysical Modeling and 3D Post-Stack Seismic Inversion for Reservoir Characterization of Pab Sandstone, Zamzama Area, Southern Indus Basin, Pakistan (T-1535) (MFN 5875)

Abstract

A 3D post-stack seismic cube and suit of well logs for well Zamzama-01 and Zamzama-East-01 have been used for seismic interpretation, petrophysical modeling and seismic inversion in order to characterize the reservoir properties of Pab Sandstone in Zamzama area. The marked horizons and faults were modeled into a structural framework to see the depth variations after generating depth maps.3D structural depth models for Pab reservoir show a pattern of north-south oblique ramp thrusts developed on the southwest flank of the field. These thrusts are a combination of easterly vergent thrusts and counter back thrusts creating local area of ‘pop-up’ structures. The apparent different styles are a result of reactivation of earlier extensional fault systems and probably phased periods of compression. Structural modeling leads to the generation of depth static model which serves as an input to populate petrophysical properties for generating reservoir model using Sequential Gaussian Simulation. In south-western part of the study area, the calculated petrophysical properties depicts good reservoir conditions, whereas in north-eastern part, reservoir conditions are poor at deeper levels. Model Based Inversion (MBI) has been performed to calculate the acoustic impedance which show changes in the impedance values from low to high moving from south-west to north-east which depicts decrease in porosity. A correlation exits between the porosity calculated from seismic inversion and porosity calculated from petrophysical analysis for petrophysical modeling which makes these results reliable.