Abstract:
The Balkassar Oilfield lies in the south-southeast of the Salt Range-Potwar foreland basin (SRPFB). It is the result of Tertiary Himalayan collision between the Indian and Eurasian plates. The Himalayan thrusting and folding formed the structural traps in SRPFB. The Balkassar Oilfield is one of the oldest known oilfields of Pakistan producing oil since 1945. It was discovered on the basis of surface geological data. The main objective of this study includes the structural interpretation, petrophysical and attributes analysis of the Balkassar Oilfield. The interpretation included the construction of Time and Depth contour maps of top Eocene (Chorgali Formation) and Paleocene (Lockhart Formation) using 2D seismic lines. The well data of Balkassar-OXY-01 is used to correlate and interpret the structure properly and to generate the surface maps also Sonic Log, Neutron Porosity Log, Density Log, Gamma ray Log, Gamma Ray Spectrum, SP Log, Resistivity Logs, Photoelectric Effect Log were analyzed. These logs were used to determine Mineralogy, Petrophysical characteristics and Seismic parameters to obscure the Reservoir properties. Seismic attributes are run on seismic line PBJ-04 for lithological and Petrophysical prediction of reservoirs. It is concluded on the basis of this study that the Balkassar structure is appeared as broad, gentle Dome shaped Structure, which is nearly flat on the top, bounded by Thrust Faults. These thrusts and Back-thrust in SRPFB are the result of Northwest-Southeast Himalayan compression. The fractured carbonate of Chorgali Formation of Eocene age is the major producing reservoirs in the Balkassar area. The clays of Murree Formation, due to juxta position, act as seal along the main fault, while on rest of the sides; dips provide the closure, by making structure favorable for hydrocarbon accumulation.
