SEISMIC DATA INTERPRETATION AND PETROPHYSICAL ANALYSIS, FIMKASSAR AREA, UPPER INDUS BASIN, PAKISTAN

Abstract

Fimkassar is situated in Punjab, Pakistan. It is 517 m above sea level in terms of elevation. The area is a part of Chakwal district and lies at a distance of 72 km south of Islamabad in Potwar sub-basin region of the Upper Indus basin. Five Migrated seismic lines were assigned of Fimkassar area and well logs of well Turkwal Deep 1 of the Potwar foreland basin. This data was given to us for seismic interpretation and petrophysical evaluation of that area respectively. All data was taken from DGPC, Islamabad, Pakistan. Seismic lines 884-FMK-102 and 884-FMK-107, and seismic lines 884-FMK-104 and 884-FMK- 106 are oriented NW to SE and SE to NW respectively. While, 884-FMK-103 is oriented S-N. the subsurface structural interpretation of the area was done on the basis of velocity data obtained which further helped in the conversion of time into depth sections. Two reflectors were marked with Chorgali Formation (Top Eocene), and the Sakesar Limestone. Thrust faults were marked, and then time contour maps were generated. Time sections were converted into depth sections with the help of average velocity and finally depth contour maps were generated. The major causes have been the thrust faults that evoked from the basement salt movement to form anticlines. Hydrocarbon traps were most possibly developed in these anticlines and are the prospective zones for hydrocarbon accumulation in the Fimkassar area. Petrophysical evaluation of well Turkwal Deep-1 was carried out to highlight the reservoir area which included the selection of zone of interest followed by Log interpretation. The volume of shale, porosity, permeability, saturation of water, and hydrocarbon saturation was interpreted. On the basis of petrophysical evaluation it was noted that the reservoir of Eocene (Chorgali Formation and Sakesar Limestone) bore good porosity but was lacking hydrocarbon potential. These conditions made the well uneconomical and was abandoned.