Geochemical Analysis and Source Rock Evaluation of Paleocene Ranikot Formation of Kirthar Fold Belt, Lower Indus Basin, Pakistan

Abstract

The Ranikot Formation, a significant geological unit in the Southern Indus Basin's Karachi Trough, has been subjected to extensive geochemical investigations using a variety of techniques to gain insight into its hydrocarbon potential. Total organic carbon (TOC), Rock-Eval Pyrolysis (RE), and organic petrography (vitrinite reflectance and maceral analysis) conventional techniques employed on well cuttings of the Hundi-01 well to find out Ranikot Potential. These methods were used to evaluate the level of organic richness, thermal maturity, kerogen and maceral type, and hydrocarbon type. TOC was also analyzed using unconventional methods includes Fertl and Chilingar method, Passey method to establish correlation of TOC. According to well cuttings organic richness average values is 2.15 wt. % and Ranikot Formation belongs fair to excellent category. Predicted logs TOC averages are 1.52 Wt. % and 1.18 Wt. % for Passey (ΔlogR) method and for Fertl and Chilingar (SGR) method accordingly with coefficient of determination R2 of 0.82 and 0.39 respectively suggesting that Ranikot Formation falls in fair to excellent category. RE parameters classified Ranikot Formation as a good oil and gas source with Type II & III kerogen and has potential to generate hydrocarbon in peak to late maturation window and has poor generative potential. Ro value lies from 0.90-1.27 % which suggested that Ranikot Formation belongs to peak to late oil maturity window. Collinite and telinite are the first dominant vitrinite, Inertinite is the second major maceral, solid bitumen is third dominant maceral and trace amounts of Liptinite is also observed as a Liptoditrinite and Alginite. The current research demarcates that Ranikot Formation as a potential source rock in Karachi Trough’s Hundi-01 well of the Lower Indus Basin.