http://hdl.handle.net/123456789/10352 2026-04-04T12:26:55Z http://hdl.handle.net/123456789/19033 2-D Seismic Data Interpretation of Qadirpur Area, Pakistan Ammad Ali Tariq Aim of the study is to interpret 2D-Seismic Reflection time section of the Qadirpur Area (Sindh Province) Pakistan. This seismic section is a Pre-stacked time migrated section and was provided by the Department of Earth Sciences, Bahria University Islamabad and this line bears the title 985-QPR-03 It is about 40 Kms in length and is oriented in SW-NE direction. OGDC acquired data in October 1998 and processed it in January 1999. The velocity information is in the form of RMS. DIX interval and DIX average at different times is given, and is provided at selected S.P. RMS velocity varies from 1500 m/s to 5000 m/s Interpreted part of this line from S.P. # 460 to S.P # 720, with CDPs from 920 to 1440 Length of this part of seismic section is 13 Kms. For interpretation of this part of Seismic section, four reflectors and 2 faults are marked on the basis of prominent reflections from subsurface horizons due to changes in lithology and diffractions. Using the RMS velocity given in the velocity panels on seismic section for selected shot points, calculate the time on constant velocity interval of 100m/sec Then using these calculated time and velocity values prepare the Iso-velocity graph and Iso-time graph (for mean line method) by taking constant velocity and time respectively, In Mean line Method of velocity estimation, a velocity vs time graph is prepared. From this graph, a mean average velocity is determined. From Seismic Section, arrival times (two ways) of each marked reflector are determined, Using these arrival times, Time Section is prepared. Also using these arrival times, calculate the average velocity for these times on mean line graph and then the depth of each reflector has been calculated using s(vt)/2 and is represented in Depth Section. Depth Section provides a reliable picture of reflectors and structures present in the subsurface of the area. Well correlation is also done, which satisfy the calculated depths, so horizons have been marked Interpretation of the Project Area shows that, extensional regime and calm environment prevails in the area. Reflectors are almost flat-lying, whereas Horst and Graben structures have been found. Supervised by Mr. Rashid Jamil 2907-01-01T00:00:00Z http://hdl.handle.net/123456789/19998 AVO Forward Modeling and Gassmann Fluid Substitution Analysis of Sanghar Area, Lower Indus Basin, Pakistan Muhammad Arshad, 01-262222-021 This dissertation contains the study and interpretation of 2D seismic reflection data of selected seismic lines of Sanghar area, Lower Indus Basin, Pakistan. The main objective of this research was delineation of subsurface structures favorable for hydrocarbon accumulation and attributes analysis. This area is situated in the Sanghar District of Sindh Province and is licensed to Oil and Gas Development Corporation Limited (OGDCL). The seismic data for this dissertation was provided by the Land Mark Resources (LMKR) by the permission of Directorate General of Petroleum Concessions (DGPC). The data comprised six seismic lines, well tops of well Sono-2, and Sono-5. The names of lines obtained are: (872-SGR-510, 862-SGR-140, 862-SGR-161, 862- SGR-162, 862-SGR-163 and 872-SGR-509). Three horizons are marked and named after correlating with well tops of Sono-2 and 5, after well to seismic tie these horizons are correlated in whole area. In time structure maps, it was found that the area is under the Extensional Tectonic Regime which produced the Normal faulting in the region. Major Horst and Graben structures are formed due to the process of rifting. Time and depth contours were generated for structural delineation. Petrophysical analysis confirms that Lower Goru formation are acting reservoirs in Sono-2 and Sono-5. Seismic inversion helps to determine the acoustic impedance for the interested formations. The acoustic impedance for Lower Goru formation lies between 9554 & 9525 ((m/s)*(g/cc)). Gassmann fluid substitution is applied for discrimination of fluid within the interested reservoirs of Sono-2. By using Zoeppritz calculator, reflection coefficient curves as a function of angle of incidence for Zoeppritz and its approximations Shuey 3 terms giving a clear indication of oil and gas reservoirs. Supervised by Dr. M. Fahad Mehmood 2025-01-01T00:00:00Z http://hdl.handle.net/123456789/19947 Enhancing the Resolution of Subsurface Geology by Applying Broadband Processing Techniques and Full Waveform Inversion in Offshore Sudan Red Sea, Northeast Africa Najwa Ahmer Abbasi, 01-262232-020 Salt bodies, sharp velocity differences, and numerous reflections make imaging subsurface geology in offshore Sudan, which is part of the tectonically complex Red Sea Basin of Northeast Africa, extremely difficult. By applying Full Waveform Inversion (FWI) and sophisticated broadband seismic processing techniques to 2D marine seismic data obtained from Offshore Block 13, this work seeks to improve the resolution of subsurface features. After reformatting and geometry assignment, the processing methodology included thorough noise attenuation using Plane Wave Dip Filtering (PWDF) for linear noise and Time-Frequency Denoising (TFDN) for swell noise. The vertical resolution was improved, and lost frequency content was recovered with the successful removal of source and receiver ghosts through subsequent deghosting using the DUG Broad method. After that, designature techniques were used to recover the true wavelet shape and account for bubble effects. To suppress both shallow and deep-water multiples, Surface-Related Multiple Elimination (SRME) and High-Resolution Radon Transform were used in succession. An original model utilized in Pre-Stack Depth Migration (PSDM) was created by combining traditional semblance analysis and tomography with velocity model development. However, a second seismic line with more distinct salt geometry was chosen for FWI because of the constraints in imaging beneath salt formations. By decreasing the mismatch between the synthetic and observed data, FWI iteratively updated the velocity model, starting at a frequency of 6 Hz to prevent cycle skipping. Reflector continuity and seismic event location were greatly enhanced by the final FWI-refined model, especially over the unconformity and under the salt. The FWI-updated model was used to create the final PSDM stack, which improved subsurface resolution, geological structure delineation, and confidence in stratigraphic and structural interpretation. This integrated technique is crucial to assisting hydrocarbon exploration efforts in the Red Sea region and shows that integrating broadband processing with FWI is a potent strategy for addressing imaging issues in offshore basins influenced by salt. Supervised by Dr. Urooj Shakir 2025-01-01T00:00:00Z http://hdl.handle.net/123456789/19946 Assessment of Pore Pressure Prediction Methods for Accuracy and Precision Using Geophysical Data: A Review of Balkassar Oil Field, Pakistan Usama Zahoor, 01-262232-022 Pore pressure prediction is significantly important for successful drilling and completion of exploration/development wells. Unrestrained geopressure conditions can lead to well abandonment which costs billions of dollars’ loss to the oil and gas companies. The Potwar Basin, a significant hydrocarbon-producing basin of Pakistan, experiences severe drilling problems owing to abnormal pressures reported in the subsurface. Geopressure analysis is carried out in this study for a constrained pressure prediction model by integrating well and seismic data. The demarcation of structural geometry is critical in understanding abnormal pressures for which seismic interpretation is performed. Log-based pore pressure prediction using Eaton’s, Bower’s and Equivalent Depth method is then employed on the wells selected from the study area to identify the overpressure intervals and check which method provides the best of its accuracy. The predicted pressures are calibrated with the measured pressure of Balkassar OXY-01 well to validate the results. Seismic inversion followed by neural network analysis is then applied to determine the spatial and vertical pressure variations within the reservoir zone. A combination of linear regression method with Probabilistic Neural Network (PNN) is applied to predict 2D pressure sections. Based on the results of the log-based pore pressure prediction, Eaton’s and Equivalent Depth Method provided promising results having well-constrained predicted geopressure curves validated with the measured pressure. However, pressure predicted from Bower’s method showed significant variations. Therefore, predicted pressure curves from Eaton’s and Equivalent Depth Method were further used to compute the seismic-based pressure section. The results showed significant overpressured intervals within the post-Neogene sediments whereas, pre-Neogene carbonate rocks exhibit underpressured to hydrostatic conditions in the study area.Pressure estimation using Bower’s Method reached around 5000 psi in Balkassar OXY-01; 5500 psi in Balkassar OXY-02 and 5000 psi in Balkassar POL-01 in the murree formation, but with low precision. Eaton’s Method provided a more consistent result of 4200 psi in Balkassar OXY-01; 4700 psi in Balkassar OXY-02 and 4400 psi in Balkassar POL-01, while the Equivalent Depth Method estimated pressure at approximately 4100 psi Balkassar OXY-01; 4800 psi in Balkassar OXY-02 and 4500 psi in Balkassar POL-01. Supervised by Dr. Muhammad Raiees Amjad 2025-01-01T00:00:00Z