2D Seismic Interpretation of Meyal Area, Potwar Basin, Pakistan

Abstract

The study area (Meyal) is bounded by latitudes 33°22′N and longitudes 72°18'E and is a part of the Meyal block which lies in the northern part of Potwar sub-basin ie North Potwar Deformed Zone (NPDZ) We obtain the seismic lines (a total of 7), seismic base map and well data (MEYAL-05) and Vertical Seismic Profile (VSP) data of well (MEYAL-08) from Landmark Resources (LMKR) with the prior approval from the Directorate General of Petroleum Concession (DGPC) We Identify key seismic reflections using well data and Vertical Seismic Profile(VSP) These reflectors are R1(Kohat), R2(Datta), R3(Chorgali) Reading of time against each 10 shot point interval for one reflector RI(Kohat) and Posted of that time on the base map and construction of time contour map. Construction of Time, Velocity and Depth contour map on top Eocene. Construction of Geoseismic/Depth section of line 0/801-MYL-10. The velocity graphs show that the velocity falls in the range between 2000m/sec to 5000m/sec along this structure. The maximum depth of basement is 7800m. In Meyal Chorgali and Datta Formations are major producing reservoir rock. Core analysis from Meyal oilfield shows that the primary porosity is less than 1% in the Chorgali and Sakesar limestones. The gray shales of the Mianwali (Triassic age), Datta (Jurassaic age) and Patala Formations (Paleocene age) are potential source rocks in study area (Meyal), these formation include 27% to 36% total organic content (TOC) in isolated pockets of shales. The Kuldana Formation (Eocene age) acts as cap for the reservoir. The time, velocity, depth contour maps and their respective surfaces of RI (probable top Eocene Kohat formation) shows that the subsurface structure is a faulted anticline. Thrust faults are NW-SE trending. The axis of the anticline is in the East-West direction and the faulted anticline plunges in both East and West directions. The depth section for the line 0/801-MYL-10 (dip line) shows that i.e. North dipping thrusts and South dipping back thrusts.