Source Rock Characterization of the Ranikot Formation Using Seismic and Well Logs Data, Gambat Block, Lower Indus Basin, Pakistan

Abstract

Gambat is the study area situated in Khairpur District in Sindh, Pakistan. Gambat block is part of the Lower Indus Basin, an extensional regime that results in widespread horst and graben geometry, which can be considered possible hydrocarbon zones. Stratigraphic and structural traps both are present in this area. The study's objectives were the characterization of source rock, which was done by the estimation of TOC by using well logs and well cuttings, using well logs different methods which include Schmoker and DLogR. The results from both well logs and well cuttings were correlated in which the resistivity method by DLogR was the best approach with the correlation and (R2) values of 0.96 and 0.92, which is considered very good. A petrophysical analysis was performed to determine the porosity, permeability, and saturation of water. The results from petrophysics showed that there is 86% saturation of water and 14% saturation of hydrocarbon. The seismic interpretation was performed to understand the subsurface geology for hydrocarbon accumulation, and the horst and graben structures were identified. A comparative analysis was performed between Talhar Shale and Ranikot Formation by using the data from the literature, in which Talhar Shale performed better with the results. The study is based on all the objectives to characterize source rock and to contribute to future findings of hydrocarbons in Lower Indus Basin, particularly Ranikot Formation.