Seismic Interpretation of Basal Sands of Lower Goru Formation with Attribute Analysis and Petrophysical Analysis of Well Data, Sinjhoro Block

Abstract

This thesis presents 2D seismic interpretation of Basal Sands of Lower Goru Formation, along with the petrophysical analysis of well data in Sinjhoro Block, Sanghar area, Lower Indus Basin of Pakistan. The seismic and well data was acquired from LMKR, Pakistan and it comprises of seven seismic lines and three wells. The study area is located in the southwestern periphery of the Indian plate and is present in extensional regime showing normal faulting with horst and graben structures. It holds all the major elements of petroleum system verified by a number of oil and gas discoveries such as Chak-2, Hakeem Daho, Lala Jamali and Resham wells. The key objectives of this research are to define the subsurface geometry by generating subsurface maps using seismic technique, identification of any prominent lead and determination of its sealing capacity, and to evaluate hydrocarbon potential and reserve estimation using wireline log data. Methodology adopted to achieve these tasks includes structural interpretation along with seismic attribute analysis and their integration; and petrophysical analysis and reserve estimation. Seven horizons along with faults were marked on seismic sections. A velocity model using well velocities was created for the reservoir i.e. Basal Sands which was later utilized in depth contour mapping. A structural closure and prospective lead were identified on depth contour map of Basal Sands of Lower Goru Formation. Fault seal analysis was performed for the confirmation of the sealing potential of the fault along which the prospective lead was identified. Trace-based seismic attributes supported the structural interpretation whereas map-based seismic attributes highlighted the hydrocarbon-containing areas with amplitude variations. Producing zones of Basal Sands of Lower Goru Formation were identified through petrophysical analysis and the results were later used in estimation of reserves.