GEOCHEMICAL CHARACTERIZATION OF SOURCE ROCKS AND OIL-SOURCE ROCK CORRELATION IN SOME WELLS WITHIN SOUTH UMBARKA AREA, NORTH WESTERN DESERT, EGYPT. LOBNA M. SHARAF and 1MOHAMED M. El NADY Dept Geology, Fac. Sciences, Ain Shams Univ., Egypt; 1Explor. Dept. Egyptian petroleum Research Inst., Cairo, Egypt Geochemical analyses of rock samples from different wells within South Umbarka area, in the North Western Desert, suggest effective source rocks within Alam El Bueib, Khatatba and Kohla Fms. Biological marker analyses of Alam El Bueib and Khatatba extracts suggest mixed organic sources with more contribution from terrestrial organic matter deposited in a clay-rich marine environment. On the other hand, mass fragmentograms of Kohla extract suggest terrestrial, bacterial and algal precursors with limited input of marine organic matter. Oils from Alam El Bueib and Bahariya reservoirs are genetically related, multisourced from Khatatba and Alam El Bueib source rocks with minor contribution from Kohla source rock. However, minor biomarker differences suggest a more contribution from Upper Cretaceous carbonate source rocks to oil of Bahariya reservoir.