An Integrative Modeling Approach to Estimating Volume of Generated Oil from Lower Cretaceous Sulaiy Formation in Southern Iraq

Abstract

Thermal maturity and petroleum generation capacity of the source rocks of Lower Cretaceous Sulaiy Formation were studied and evaluated via modeling the thermal maturation of ten wells in this study by using the Arrhenius equation for chemical reactions or (time-temperature index of thermal maturation). A thermal maturation map of the Sulaiy Formation shows that it a high maturity level increasing eastward; also, the geochemical analysis indicated suitable organic content in quantity and quality to generate hydrocarbons. The onset of oil migration from the Sulaiy Formation is calculated by this study to be at the end of Lower Eocene time (53 million years ago), and as it is a late hydrocarbon generation and migration; thus indicating mainly vertical migration paths. According to quantitative estimation, the oil generated and migrated vertically from the Sulaiy Formation towards the Lower Cretaceous reservoirs in southern Iraq estimated at 42.6 x 109 bbl. This study elevated the status of the Sulaiy Formation to a major source of oil tapped in the Lower Cetaceous reservoirs of southern Iraq.