2D Seismic Data Interpretation, Petrophysical Analysis And Volumetric Reserves Estimation Of Shahdadpur Gas Field, Lower Indus Basin, Pakistan

Abstract

The research was conducted to reveal the subsurface geology of the Shahdadpur area by using the seismic interpretation technique and the hydrocarbon saturation was estimated to find the potential reserves by using petrophysical techniques. Seismic data interpretation plays a crucial role in exploring hydrocarbons and understanding the geology beneath the earth's surface. The study area has an extensional basin regime followed by normal faults that are marked in interpreted seismic sections F1, F2, F3, F4, and F5. By observing these faults, the area has horst and graben structures which helps in hydrocarbon accumulation. Sembar Formation was the major source rock in the study area and the reservoir Formation was Lower Goru and Chiltan, and Upper Goru acts as seal rock that completes the petroleum system. In this research, two horizons were marked on a seismic section named Lower Goru of the Cretaceous age and Chiltan Limestone of the Jurassic age and then the time and depth contour maps were generated for both marked horizons. Petrophysical analysis was performed on the Lower Goru Formation in which three hydrocarbon-bearing zones were identified that was based on log trends. Overall, the average values of the volume of shale, a saturation of hydrocarbon, and effective porosity in these zones were 49.9%,40.4%, and 9.1% respectively. By using seismic results of the depth contours map of the Lower Goru Formation and petrophysical analysis that was done on the Lower Goru Formation, volumetric reserves estimation was computed to identify the maximum hydrocarbon extent which indicates the more presence of hydrocarbon availability while proceeding toward the advanced seismic interpretation.