INTEGRATED SEISMIC AND WELL LOG INTERPRETATION FOR CHARACTERIZATION OF BALKASSAR FIELD, UPPER INDUS BASIN

Abstract

The dissertation work includes interpretation of seismic data, Petrophysical analysis using well logs data, facies identification, and rock physics as well use of seismic inversion to estimate physical properties of rocks. The study area selected for this purpose is Balkassar area (Upper Indus Basin) Pakistan. The purpose of this research is to study structural variations of subsurface using seismic and well log data of Balkassar area. The data used for this work consist of 3 seismic lines i.e two dip and a strike line. The area is a part of Potwar sub-basin which is known for its hydrocarbon structural traps. Patala formation acts as a source rock, Chorgali and Sakesar formation acts a reservoir rock whereas Murree formation acts a seal/cap rock. The seismic interpretation shows anticline structures bounded by thrust faults. Two-way fault bounded closure is clearly observed on the time and depth Contour maps which confirms the presence of pop up structure in the study area. Petrophysical analysis of well BALKASSAR-OXY-01 is carried out for Chorgali and Sakesar in order to depict the probable hydrocarbon producing reservoir. I have marked one zone in chorgali formation having water saturation 33% and hydrocarbon saturation being 67%. Three probable zones were marked in sakesar formation among which zone C have water saturation 29% and hydrocarbon saturation 71%. In rock physics plots of elastic moduli with reservoir depth shows low values of moduli in productive zone which also confirm our Petrophysical interpretation Coloured inversion results are also demonstrating that Chorgali and sakesar act as a reservoir. On inverted section Chorgali and Sakesar shows low value of impedance i.e. strong indicator for the presence of hydrocarbons.