The Zohr Biogenic Gas Discovery: an Initial Assessment of Controlling Factors in the Petroleum System

Summary The deepwater biogenic gas discoveries in the Eastern Mediterranean have unique characteristics, especially due to the Messinian Salinity Crisis (MSC) between 5.96 and 5.33 Ma during which most of the Mediterranean and connected basins lost all or most of their water coverage. This resulted in geologically rapid changes in depositional environments and in the surface and subsurface conditions. The role of the MSC in the formation and preservation of hydrocarbon accumulations in the area is an ongoing discussion. What are the relationships, if any, to the MSC? Are there features that are unique and limited to areas affected by the MSC? How does the event control the risks associated with the generation, migration, accumulation, preservation and loss of the hydrocarbons? What do we know about the charging conditions and mechanisms? Are there controlling processes that occur on very short geological time scales? We use analogues and petroleum systems modeling to investigate hypotheses related to the generation, migration and entrapment of biogenic gas fields in connection with the MSC. A conceptual 2D petroleum systems model of the Zohr discovery is constructed based on publicly available data, and used to constrain our understanding of the properties and processes in the petroleum systems.