The Black Sea Province has an exploration history that dates back more than a century. One of the oldest discoveries, Priozernoye, was made in 1886 on the basis of seeps in the easternmost part of the Crimean Peninsula, within the Indolo-Kuban foreland basin of the Caucasus Province. For many years, due to the aftermath of World War I, exploratory drilling was intermittent. In 1939, the Supsa oil field was discovered in the Rioni Basin of Georgia; the prospect had originally been drilled in 1886, but the flow rates were noncommercial. More systematic exploration was undertaken by newly formed state compa-nies after World War II. The introduction of geophysical techniques led to the identification of thick sedimentary sequences in areas such as the Moesian Platform, previously considered of marginal prospectivity. A gas blowout in 1951 marked the discovery of Tyulenovo, which was to prove to be Bulgaria's largest field. Its coastal location and extension offshore first demonstrated the potential of the Black Sea. Further encouragement was provided in the mid- 1950s by the Kamchiya gas discovery and the opening up of the Romanian sector of the Moesian Platform. The gas/condensate play of the Black Sea-Crimea Basin was established in the 1960s, at the time offshore exploration began. Surveying was first undertaken offshore Bulgaria (with Soviet assistance), and by the early 1970s most countries were actively surveying the Black Sea. Drilling began offshore in the 1970s when Westates drilled two dry new-field wildcats in the far west of Turkish waters. The first offshore discovery was Golitsyna in 1975, on the Odessa Shelf, and when brought onstream in 1983 it became the first producing gas field in the Black Sea. Drilling off Romania began in 1976 (the same year that the Turkish state company TPAO made a subcommercial gas discovery with Akgakoca 1) and led to the discovery of the Lebada Est in 1981; oil production started in 1987. The breakup of the Soviet Union and the revolutions of Eastern Europe mark a new phase of exploration, with foreign companies taking a leading role. As yet, no deep-water wildcats have been drilled, and the limited exploration on the western Black Sea shelf has resulted in 14 discoveries (3 oil and 11 gas) and aggregate reserve additions estimated at 630 MMBOE.
Figures & Tables
Regional and Petroleum Geology of the Black Sea and Surrounding Region
In 1967 and 1969, two oceanographic cruises were made in the Black Sea under the guidance of the Woods Hole Oceanographic Institute: The cruises included scientists from many countries and disciplines. Their aims were to determine the recent geological and geochemical evolution of the Black Sea, to map the shallow structure of the basin, and to study the interaction between the oxidized surface waters and the anoxic waters beneath them. The results were published 23 years ago, as AAPG Memoir 20 (Ross and Degens, 1974). During the 1969 cruise, the vessel Atlantis II collected 40 piston cores, which formed the basis of most of the subsequent geological studies that were restricted to very recent sedimentation. Speculations concerning the origin of the basin and the relationship of the geology offshore to that exposed around the margins of the Black Sea were rooted in pre-plate tectonic concepts of basin formation and were in any case hampered by a lack of relevant data (Brinkmann, 1974).
In 1976, the Glomar Challenger visited the Black Sea on Leg 42B of the Deep Sea Drilling Project and drilled and cored three deep-water sites (379, 380, and 381). Well 381 north of the Bosporus encountered sediments as old as Miocene, including some apparently deposited in shallow water (Ross, 1978).
The next major volume in Western literature to deal with the Black Sea was published a decade later, collecting papers presented two years earlier at a conference in Yalta. In this volume, a number of seismic reflection lines