Structural Interpretation of Missa Keswal using 2D Seismic Data (T-1356) (MFN 2231)

Abstract

Seismic lines PBJ-5 and PBJ-] O. obtained from Directorate General of Petroleum Concessions (DGPC). was shot by OGDCL in ] 980 in the area or Balkassar which lies in the Central Potwar on the southern flank of Soan Syncline. Seismic line PBJ-5 is a dip line and PBJ-]O is a strike line. T\vo prominent reJ1ectors Rl (Eocene). and R2 (Basement) were marked on the seismic section on the basis of observed rellcction events. A nwlt was marked which continued along the Pre-Cambrian basement. T\vo more thrust faults were marked which showed fault-propagating folds in tbc form of anticlines of Balkassar. A time section was produced from the seismic section Llsing the vibrating points and the two-way-times (TWT) or the reflectors and f~tLIlts. The TWT were posted on the basc map to make a time contour map or the Upper Eocene Chorgali Formation, as it was continuing throughout the area. The seismic velocities (Interval Velocity), given in the velocity windows on the seismic section. were llsed to find the average velocities of the Upper Eocene Chorgali Formation and the PreCambrian basement. These average velocities were then used to find the depths of the formations for the geoseismic section. Well claw of Balkassar OXY#l was used to mark the thickness of the Il1diviclual formations on the geoseismic section from Cambrian to Recent. The geoseismic section showed that the area was structurally deformed due to salt decollement and compressional tectonic movements. Traps for hydrocarbons were devcloped in thc anticlines as they truncated agai nst the thrust fault. Salt probably moved into these anticlincs due to compressional movements and a Pop-Lp structure was formed. The Balkassar anticline \vas the prospcctive zoncs and was the primary targets for oil exploration. where the depth or the Upper Eocene formation \vas almost 2400111. favorable for drilling.