International Black Sea Coastline Countries Scientific Research Symposium - IV, Giresun, Turkey, 5 - 06 May 2020, pp.21-34
The Marmara Sea (Northwestern Turkey) is an enclosed sea that hydraulically establishes a connection between the Mediterranean and Black Seas and located on the northern branch of the North Anatolian Fault Zone (NAFZ). In the previous field observations in the Marmara Sea, the extensive areas that exhibited active seafloor fluid seepages along the NAFZ have been identified. It has been widely reported that hydrocarbon-rich fluid discharges on the seafloor, often associated with chemosynthetic communities and authigenic carbonate deposits. The authigenic carbonates have been revealed both at the seafloor and within the sediments at various locations in the Marmara Sea. Moreover, the expulsion sites where the main fault crosses topographic highs present evidence for deep-sourced fluids including thermogenic gas. The fluids being expelled are the brines with exotic fluid chemistry along with thermogenic gas and oil. Hydrocarbon-show wells, cold seeps, and mud volcanoes are evidence for the working petroleum systems in the Marmara Sea Therefore, in this study, the hydrocarbon exploration activities in the past and seafloor indications for oil and gas potential in the Marmara Sea are evaluated. In the wells drilled in the Marmara Sea by Turkey up to this time, any economic hydrocarbon discovery could not be brought to a successful conclusion up to now. However, the geological, geochemical, and geophysical data presented in this investigation manifest that oil and gas reserves may be discovered in Tekirdağ, Central, and Çınarcık basins and highs which are the sub-basins of the Marmara Sea Basin. To sum up, it is anticipated that the future hydrocarbon exploration practices may promote the discovery accomplishments if they are shifted to the projected areas and drilling locations recommended in this study.