Study of Geological Interpretation using Petro-physical Analysis, Facies Analysis and Colored Inversion of Bitrism Area Southern Indus Basin, Pakistan

Abstract

Interpretation of two dimensional Seismic lines obtained from a survey conducted in the Bitrism block, Southern Indus Basin by means of Time and Depth contour maps and fault polygon maps for the Upper and the Lower Goru Formations portrays presence of extensional regime as major normal faults form Horst and Graben structures with probable hydrocarbon saturation. The shales present in the Lower Goru formation acts as a source while the sand present in the Lower Goru formation acts as a reservoir. Interpretation shows that the Upper Goru formation acts as a seal rock Cross plot between GR log, NPHI log and RHOB log shows presence of major shale lithologies with interbedded sand lithologies. This has been confirmed using various other cross plots like a cross plot between GR log, LLD log and RHOB log as well as DT log, RHOB log and GR log as reference log. Rock physics shows saturation of the target zone. Petro-physical analysis of the Lower Goru formation shows 60% volume of shale. The Petro-physical analysis of the reservoir zone shows 29% shale presence with hydrocarbon saturation of 81%, water saturation of 19% and effective porosity of 27.5%. Colored inversion shows low Acoustic Impedance present in the zone of interest referring to presence of hydrocarbons as velocity and density values are low.