2-D Integrated Seismic Interpretation, Attributes Analysis, Petrophysical Analysis, Rock Physics based Facies Analysis and Velocity Modeling of Sinjhoro Area.

Abstract

The main purpose of the study is to evaluate hydrocarbon potential of Sinjhoro area that lies in Sindh monocline, Southern Indus basin for delineation of potential leads for future prospects. This is done through interpretation of 2-D seismic and wire line log data, which have been obtained through the permission of Directorate General of Petroleum Concessions, Islamabad, Pakistan. This dataset comprises of 13 seismic lines and a complete suite of wire line logs of 4 wells. The seismic data is utilized for the identification of structural traps, marking of the different lithological horizons and naming them using the well tops data in the area. The faults are demarcated on seismic lines to develop the structure geometry. Three prominent reflectors are marked namely Lower Goru Formation, Upper Goru Formation and Chiltan Formation. Due to the extensional tectonics the identified structures are Horst and Graben. Two-way time contour maps of the marked lithologies have been prepared to determine the spatial variation of the structures. Root mean square velocities are used to generate a geologically realistic velocity model which in turn is used for time to depth conversion. Depth contour maps are also generated for these marked lithologies. Analysis of wire line logs includes the calculation of different reservoir characteristics like Shale Volume (Vsh), Porosity (Phi), True Resistivity of formation (Rt), Density (RHOB), Water Saturation (Sw), Hydrocarbon Saturation (Shc). These parameters are further used for reservoir potential evaluation. Basal Sands of Lower Goru (Cretaceous) Formation is the primary reservoir in this area. One zone is marked in this region having the average saturation of hydrocarbon 62%. Porosities are calculated for Basal Sands of Lower Goru Formation. Average porosity of Basal Sands of Lower Goru Formation is around 14% in the prospect area. The well log data is also used for Rock Physics analysis to compute elastic logs that are cross plotted for facies modeling.