Petroleum geology of the Black Sea: introduction

Abstract

Abstract:The exploration for petroleum in the Black Sea is still in its infancy. Notwithstanding the technical challenges in drilling in its deep-water regions, several geological risks require better understanding. These challenges include reservoir presence and quality (partly related to sediment provenance), and the timing and migration of hydrocarbons from source rocks relative to trap formation. In turn, these risks can only be better understood by an appreciation of the geological history of the Black Sea basins and the surrounding orogens. This history is not without ongoing controversy. The timing of basin formation, uplift of the margins and facies distribution remain issues for robust debate. This Special Publication presents the results of 15 studies that relate to the tectonostratigraphy and petroleum geology of the Black Sea. The methodologies of these studies encompass crustal structure, geodynamic evolution, stratigraphy and its regional correlation, petroleum systems, source to sink, hydrocarbon habitat and play concepts, and reviews of past exploration. They provide insight into the many ongoing controversies regarding the geological history of the Black Sea region and provide a better understanding of the geological risks that must be considered for future hydrocarbon exploration. The Black Sea remains one of the largest underexplored rift basins in the world. Although significant biogenic gas discoveries have been made within the last decade, thermogenic petroleum systems must be proven through the systematic exploration of a wide variety of play concepts.Gold Open Access: This article is published under the terms of the CC-BY 3.0 license.The Black Sea, located between Russia, Georgia, Turkey, Bulgaria, Romania and Ukraine, covers an area of approximately 423 000 km 2 with a maximum water depth of 2245 m. Sedimentary thickness can exceed 14 km. The Black Sea holds an abiding fascination for petroleum geologists and is a true frontier basin with very few wells drilled in its deepwater sector. Abundant seepage, outcrops of potential source rocks around its margins, large potential traps imaged on seismic data, and a variety of potential reservoir and play concepts point towards considerable potential to reward the successful explorer. This volume brings together several geoscience studies (Fig. 1) that provide additional information about the origins of the Western and Eastern Black Sea basins, their tectonostratigraphic history, sedimentary fill and petroleum potential.The Black Sea and its surrounding regions have a long history of geological research: for example, it has long been regarded as the type example of an euxinic basin in which bottom water anoxia and free hydrogen sulphide (H 2 S) result in an absence of benthonic life and the preservation of organic matter (Wignall 1994). Somewhat ironically, the term 'euxinic' is derived from an ancient Greek name for the sea, Pontus Euxinus, meaning the welcoming or hospitable sea. Another ancient Greek name (probably derived from an Iranian nam...

Reassessing the Thermal Structure of Oceanic Lithosphere With Revised Global Inventories of Basement Depths and Heat Flow Measurements

“…Measurements requiring significant correction occur either on young oceanic crust or on crust with large sedimentation rates such as major deltas and sedimentary basins surrounded by elevated continental lithosphere. Measurements from the Caspian, Gulf of Mexico, and Black seas are discarded due to significant post‐Miocene increases in clastic flux in these regions, which violate the assumption of constant sedimentation rate (Galloway et al, ; Guliyev et al, ; Simmons et al, ). This procedure leaves 3,597 corrected heat flow measurements, which are then binned into 2.5 Myr windows.…”

Elemental geochemistry of the Upper Cretaceous reservoir and surrounding formations applied in geosteering of horizontal wells, Lebăda Field – Western Black Sea

“…While the deepwater concessions of Romania are only in the early exploration stage (Simmons et al, 2018), the Upper Cretaceous reservoir of the Lebăda Field located offshore Romania was discovered between 1980 and 1985, and is considered one of the most important reservoirs offshore, Romania (Fig. 1).…”

Biostratigraphy and paleoenvironments of the Oligocene succession(İhsaniye Formation) at Karaburun (NW Turkey)

“…Here, in a rock unit often referred to as the Maykop Suite, the succession often becomes clay-and sand-dominated (as opposed to carbonate-dominated as in the underlying Eocene succession) and often contains a moderately high content of organic carbon, making it a key potential source rock within the region (Bazhenova et al, 2003;Sachsenhofer et al, 2017Sachsenhofer et al, , 2018Gavrilov et al, 2017). Sandstones within the Maykop Suite succession also have potential as hydrocarbon reservoirs (Tari et al, 2009(Tari et al, , 2011Rees et al, 2018;Simmons et al, 2018;Tari and Simmons, 2018). Consequently, the stratigraphic and paleoenvironmental description of the İhsaniye Formation which is a lateral equivalent of the Maykop Suite enables an improved understanding of the regional depositional framework of Oligocene sediments in Paratethys with an impact for predicting both source rocks (Tulan et al, 2020) and reservoirs (Rees et al, 2018) of this age in the Black Sea depocenter.…”