Mineralogical and Geochemical Studies to Evaluate Middle Jurassic Khatatba Source Rock, Obaiyed Field in Western Desert, Egypt

Abstract Obaiyed Field, located in Egypt’s northwestern Western Desert, is a prominent hydrocarbon-producing area where the Upper Safa Member for Middle Jurassic Khatatba Fm. serves as a key source rock. This study integrates mineralogical and geochemical analyses to evaluate the potential for producing hydrocarbons from shale samples for four obaiyed field wells. The results of X-ray diffraction (XRD) reveal that kaolinite mineral is the dominant clay mineral, indicative of a detrital origin and the depositional environment is shallow marine. X-ray fluorescence (XRF) analysis shows high concentrations of SiO2, Al2O3, and CaO, with trace element associations supporting a terrigenous and marine depositional setting. The values of total organic carbon (TOC) lie between 0.5 and 3.90 wt%, where Rock-Eval pyrolysis indicating predominantly Type II/III kerogen, with gas & oil generation. Values of Tmax from 441°C to 457°C, along with low production index (PI) values influenced by sample treatment, confirm that this source rock reached the thermal maturity stage. The integrated geochemical indicators demonstrate that the Khatatba Formation possesses good organic richness, mixed kerogen types, and fair to good generation potential, affirming its role as a viable Western Desert’s source rock for hydrocarbons.