2D Seismic Modelling And Reservoir Characterization Using Seismic And Well Data of Balkassar Area, Upper Indus Basin, Pakistan

Abstract

The dissertation work includes seismic data interpretation, Petrophysical analysis using well logs data; for the identification of possible prospect (H.C) zones with the use of seismic inversion. Facies modeling for the confirmation of lithology’s and Rock Physics to find out the rock physical properties. Two-dimensional seismic data interpretation has been carried out in Upper Indus Basin, Balkassar area to confirm the reservoir characteristics of Chorgali and Sakesar Formation. Time and Depth contour maps of Chorgali and Sakesar help us to confirm the presence of anticlinal structure in the given area. Surface contour maps of Chorgali and Sakesar Formation give the real shape of sub-surface structure, which is anticlinal. This anticlinal structure acts as a trap in the area, which is best for hydrocarbon accumulation. Petrophysical analysis of well BALKASSAR OXY-01 is carried out for Chorgali, Sakesar formations in order to depict the probable hydrocarbon producing zones. The results suggest that both Chorgali and Sakesar Formations are producing reservoirs, we marked one zone in Chorgali having VSH 10%, PHIE 5%, SW 33% and H.C Saturation 67% and three zones in Sakesar having VSH 12-20%, PHIE 2-3%, SW 28-42% and H.C Saturation 58-72% which is most prominent and possible hydrocarbon zones. No major zones can be selected for production testing results as indicated by the high values of water saturation. Facies modeling is done for the confirmation of lithology’s for this purpose different cross plots has been generated which gives the result that we have pure limestone, and carbonaceous shale (limy shale) but didn’t get pure shale in our reservoir. Rock Physics describes a reservoir rock by physical properties such as porosity, rigidity, compressibility, properties that will affect how seismic waves physically travel through the rocks. This prepare links between seismic and properties of reservoir (petrophysics) more quantitatively. Different plots of elastic modulus with reservoir depth show low values in productive zones which also confirm our Petrophysical results. Seismic inversion results are also demonstrating that Chorgali and Sakesar act as a reservoir. The post stack colored inversion is performed to confirm the leads location. On inverted section Chorgali and Sakesar shows low value of impedance i.e. strong indicator for the presence of hydrocarbons, it is also confirmed from Petrophysical results.