Geochemical investigation of Yamama crude oils and their inferred source rocks in the Mesopotamian Basin, Southern Iraq

Ten oil samples from the Yamama reservoirs and ten extracts of purported source rocks from sixteen wells in the Mesopotamian Basin, Southern Iraq have been analyzed using GC, GC/MS and Stable Carbon Isotope. Yamama oils were non-biodegraded, moderate to higher maturity based on C27Ts of range from 0.17 to 0.77and TAS3 of 0.3 to 0.63, marine carbonate and marl source rocks, deposited under saline, anoxic conditions. Two oil groups were investigated based on the results of the geochemical analysis. These oils have similarly biomarkers ratios to those of the Middle Jurassic to Early Cretaceous source rocks in the Mesopotamian Basin.