ORGANIC GEOCHEMISTRY OF PALEOCENE – MIDDLE MIOCENE SUCCESSION, EE85-1A WELL, RAS BUDRAN, SUEZ GULF, EGYPT

Abstract

Ras Budran area is located in the central eastern offshore area of the Suez Gulf. The sedimentary successions from the Paleocene to the Lower-Middle Miocene were chosen to assess in the well EE85-1A at the Ras Budran area.Thegeochemical analysis of the Rock-Eval and vitrinite reflectance was applied for evaluating the studied Formations from the viewpoints of the petroleum systems. From which fifty-four cutting samples represented six Formations of Esna Shale (Paleocene), Thebes (Lower-Middle Eocene), Darat (Upper Eocene), Nukhul, Rudeis (Lower Miocene), and Kareem (Lower-Middle Miocene) were analyzed. The present study distinguishes three different categories of petroleum source potential. The first is very good to excellent source of Thebes Formation has 3.2 wt, % TOC and 22.1 mg HC/g rock of Production yield (Py=S1+S2) on averages. The second is fair sources of the Nukhul, the Darat, and the Esna Shale Formations of averages 1.23, 1.6 and 0.85 wt, % TOC and 1.67, 3.12 and 1.8 mg HC/g rock of Production yield respectively. The third is a poor source of both the Kareem and the Rudeis Formations of averages 1.4, and 0.95 wt, % TOC and 1.5, and 0.92 mg HC/g rock Py. The kerogen types of oil-prone (Type I) and mixed oil/gas prone (Type II) are the main OM (organic matter) constituent of the Thebes Formation of HI (hydrogen index) > 400 mg HC/g TOC and S2/S3 ratio is 6.97 mg HC/g rock on average. The results are categorized the Thebes Formation to be an effective source rock if buried enough to reach the oil window zone. The other Formations of Kareem, Rudeis, Nukhul, Darat, and Esna Shale include kerogens of gas prone (types III) and inert (Type IV) of HI (hydrogen index) < 200 mg HC/g TOC and S2/S3 ratio < 2 mg HC/g rock too.