This paper discusses the hydrocarbon potential of the Jurassic succession in a mature basin in Egypt as an
important element of a larger petroleum system study. Prior to any organic petrographic and organic geochemical
analyses, a palynological age dating of the originally undifferentiated Jurassic sequence was carried
out to identify different formations under investigation. This was based on key bioevents of some recovered
dinoflagellate cysts and the identified lithology. Palynological, TOC/Rock Eval pyrolysis (including modified
Rock-Eval methods), and vitrinite reflectance (VRo%) data from a total of 14 samples taken from the uppermost
lower-upper Jurassic sequence represented by the Wadi Natrun (Toarcian-Aalenian), Khatatba (late Bathonian-
Callovian), and Masajid (Oxfordian) formations in the Abu Tunis-1× well, are presented. In addition, two
samples from the Abu Tunis-1× well and the proximal (~32 km to the east) Siqueifa-1× well, having the
highest remaining hydrocarbon potential (S2 yields), were analyzed and their results were compared using
modified pyrolysis programs. Although the data showed a good correlation between the TAI of the palynomorph
assemblage, vitrinite reflectance, and Tmax from Rock-Eval pyrolysis in the shallower intervals, the correlation
between VRo and Tmax was poor in the lower half of the studied succession (middle Khatatba and Wadi Natrun
formations). The very low Tmax values indicate immature OM while VRo and TAI indicated middle stage of oil
window to past peak oil generation. The reason for this discrepancy is that the deeper samples are reservoir
rocks, not source rocks, and the majority of the organic matter is not composed of reactive kerogen but consists
of migrated hydrocarbons and NSO compounds. Contamination due to oil-based mud (OBM) was eliminated
because the Abu Tunis-1× well was drilled in 1969, prior to the extensive use of OBM in drilling. This study
showed that a multi-proxy approach is the best way to screen the hydrocarbon potential in a thick succession
that contains interbedded source and reservoir rocks.