Interpretation of Seismic Time Section in Joyamair and Chaknaurang Areas, Eastern Potwar, Pakistan (Line No. 881-CW-10)

Abstract

The seismic line 881-CW-10 lies in Joyamair and Chaknaurang area in the south-southeast of the Potwar foreland basin. Seismic sections are important for imaging the subsurface formations and structures of the earth and 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 constructs a reflector on a seismic time section Marking of prominent reflectors in the seismic section of this line represents Pre-Cambrian basement, Chorgali (Top Eocene) and Kamlial Formations. The depth section was constructed with the help of given velocity information. Depth section shows most probably the thin-skinned deformation in cover rocks le a thrusted salt-cored anticline. This type of structure is formed due to the movement of salt below the cover rocks. Time contour map of the area, made by time reading of Chorgali Formation in four seismic sections shows, the Joyamair and Chaknaurang anticlines and a long east-west oriented thrust fault. In this area thin-skinned deformation in cover rocks resulted in Pop-up anticlines, 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.