Abstract:
The seismic lines 93-MN-04, 93-MN-05 and 93-MN-06 lies in Joya mair area south-east of the Potwar foreland basin. Seismic sections are very important for imaging the subsurface formations and structures of the subsurface of the earth particularly for the exploration of hydrocarbons, in seismic reflection surveys the travel times are measured with waves reflected from subsurface between media of different acoustic impedance and this construct a reflector on a seismic time section. Sections show most probably the thin-skinned deformation in cover rocks i.e. a thrusted salt core anticline. These types of structure are formed due to the movement of salt below the cover rocks. In Joya Mair area thin-skinned deformation in cover rocks resulted in pop-up anticline, Snake-head anticlines, thrusted salt cored anticlines and triangle zones. These structures form compressional traps for oil and gas accumulation. There are two major breaks in the burial history of the area .One is from Ordovician to Carboniferous because the whole Potwar basin was uplifted during that time. The other is from late Permian to Cretaceous because the rocks from west to east in the Potwar Basin were eroded due to significant Pre-Paleocene tectonic uplift. Two prominent reflectors were marked on the basis of their reflection, which represent top Eocene Formations and Khewra Formation respectively. Reflectors were identified with the help of well top data. Two-way time (TWT) from the seismic sections and average velocities were used to create TWT map and then calculate the area with graph paper according to the scale of the base map. Then petrophysical study has been carried out in Joya Mair well 04, in this study we interpret the different logs and applied various techniques of petrophysics to evaluate the lithology, porosity, saturation, resistivity and the volume of shale and estimate the reservoir volume of Khewra sandstone.
