Organic Geochemical Characteristics of Pre and Syn-rift source rocks in the Geisum concession, south Gulf of Suez, Egypt

This study provides a comprehensive geochemical analysis of pre-rift and syn-rift source rocks from the Geisum Concession, Gulf of Suez, utilizing biomarker distributions, Rock-Eval pyrolysis, and vitrinite reflectance data to evaluate hydrocarbon generation potential. Total Organic Carbon (TOC) values range from 1.0 to 7.27 wt%, with pre-rift formations showing higher organic content compared to syn-rift formations. The kerogen types identified span Type I, II, and III, with pre-rift formations predominantly containing Type II kerogen, suggesting a higher potential for oil generation. Biomarker analysis reveals a strong marine influence, evidenced by the dominance of C30 hopanes and the presence of C27 steranes, with minimal terrigenous input. The C32 homohopane ratios (22S/22R) indicate that the source rocks are in the early oil window, corroborated by Tmax, PI, and vitrinite reflectance (Ro%) data. Pre-rift formations show stratified, anoxic depositional conditions, while syn-rift formations exhibit less reducing environments. These findings suggest that pre-rift formations in deeper stratigraphic sections may offer higher hydrocarbon potential, particularly in the oil generation window. The results highlight the significance of these source rocks in regional petroleum exploration.