Seismic Data Interpretation and Petrophysical Analysis of Zamzama Field, Lower Indus Basin, Pakistan

Abstract

The research area for the Zamzama gas field is located in Sindh's Dadu district, within the Zamzama block. The investigation region is in Pakistan's lower Indus basin's Kirthar foredeep. The geologic succession ranges from Jurassic through modern times. The Zamzama structure is a massive north-south thrusting anticline with an eastward trending. To interpret its structure and tectonic regime, seismic and borehole data are presented. The general geology, stratigraphy, and tectonics of the area is thoroughly investigated in order to better comprehend the tectonic evolution since Pangea's formation. Various faults and horizons of interest are marked and interpreted to determine the depth, extension, and orientation of subsurface structure. The purpose of petrophysical analysis is to investigate reservoir formation in order to determine rock type and fluid presence. Different logs, such as RHOB and NPHI, form various cross-overs, indicating the presence of fluid and porous and permeable rocks. Porosities, shale volume, water saturation, and hydrocarbon saturation are estimated, indicating that the reservoir rock has sufficient conventional reservoir rock potential for oil and gas production. Seismic post stack inversion is applied on a seismic line integrated with well data to understand the reservoir response on large scale. Model-based and Band limited inversion types are used which shows the low impedance at the depth of reservoir indicating presence of porous and permeable rock. Rock physics modeling is performed to distinguish shale and gas zones by plotting different cross plots between various rock parameters. Hence, Zamzama is a potential gas-producing field in the lower Indus basin, where the Pab sandstone and Khadro formation are abundantly producing in a cost-effective manner.