DRY HOLE ANALYSIS OF WELL BALKASSAR OXY-01, POTWAR SUB-BASIN, PAKISTAN

Abstract

The present study is carried out in the Balkassar area, Central Potwar Sub Basin. It pertains to petrophysical analysis of well log data of Balkassar oxy 01 and seismic interpretation of dip lines PBJ-04, PBJ-05, PBJ-06, and strike line PBJ-09. The Well is located about 656 feet Southwest of shot.172 on seismic line PBJ-4. The well had a target depth of 3130m, and hydrocarbon potentials were not tested due to no hydrocarbon shows during drilling. The well is drilled up to the Pre-Cambrian Salt Range Formation. The well was declared dry and plugged abandoned. Seismic Interpretation includes horizon marking, fault marking, and delineating the Balkassar anticlinal pop-up structure. Two-way time (TWT) contour mapping is done at the level of Chorgali Formation, Lockhart Formation, and Tobra Formation. 3D models are also generated to clearly see the entrapment mechanism of the Balkassar anticline. Petrophysical studies include calculation of Shale volume, porosity, and proportion of water content in the Chorgali Limestone and Sakesar Limestone. Vsh (volume of shale) varies from 2-20%. Average porosity trend indicates poor reservoir quality, which is from 1-3% in Hydrocarbon bearing zones in Balkassar oxy 01, indicating tight reservoir conditions. The results show that water saturation is from 60 – 95 %, which exceeds the general value suitable for hydrocarbon accumulation. Well correlation shows a homogeneous sequence of Chorgali and Sakesar Formations in wells Balkassar 01A, Balkassar oxy 01, and Balkassar 07. The distance between the well Balkassar oxy 01 and Balkassar 07 is only 1.8km approx. And Balkassar 07 is an oil well. The fracture network is not present between these wells; the phenomenon of compartmentalization is also occurring in the structure the eastern flank is not in contact with the western flank that is why the Balkassar oxy 01 is a failure. The lower reservoir horizons of the Balkassar structure have considerable hydrocarbon potential, i.e., Tobra Formation, which was not tested by oxy, should be tested.