Abstract
Different oil samples were collected from oil fields in the North Western Desert; namely, Meleiha, Razaak, and North Qarun fields. These oils were analyzed geochemically, including sulfur content, American Petroleum Institute (API) gravity, and gas chromatography The results showed that API gravity and sulfur content indicate that the crude oils have high mature level of marine origin. Distribution of n-alkanes (Carbon Preference Index [CPI], pr/ph, and isoprenoide/n-alkanes ratios) reflects that the oil samples originated mainly from marine organic sources deposited in a reducing environment. This indicates that the oil samples under investigation are well correlated with each other in the western part of the North Western Desert.