Compaction and Migration of Hydrocarbons in East Baghdad Oil Field

Abstract

An attempt is done to present a simple concept to combine the geochemical results with the concept of compaction- abnormality, reflecting a high variation in the porosity and internal pore pressure. The different compaction levels and the variation of the bulk volume may lead to the expulsion of fluids both hydrocarbon and interstitial H2O from high potential zones towards low potential zones, or in other words from low porosity towards high porosity areas. Furthermore, the both formations (Ratawi and Zubair) of lower Cretaceous age showing compaction trend as well as fluid expulsion current with a NW-SE trend of the primary hydrocarbon migration, while the sedimentary basin revealing a deepening towards the southern eastern part of the anticline structure. A change in thickness and the facieses of the rock packages is manifested. The horizontal porosity distribution of shales in Ratawi formation particularly in the upper part (15m thick) reveal differential compaction and such a mechanism is responsible for the kinetic of fluid and gas.