About Relations between Natural Gas and Oil in Connection with Forecast of Their Reserves in Azerbaijan

Azerbaijan is one of the oldest oil and gas provinces, where more than 2 bln tons of oil have been extracted over more than a century. At present, the oil production is declining and mainly determined by production from the Azeri-Chirag-Guneshli offshore block (AChG). Compared to oil, the opportunities for further growing natural gas reserves and production are very promising. For the latest years, a number of large gas condensate fields have been discovered in the deep-water part of South Caspian Sea, such as Shakh-Deniz, Apsheron, Umid. There are a number of prospects that have not yet been drilled in this part of the sea basin. The paper assesses their prospectivity, substantiates the priority exploration targets and, on the basis of the statistical analysis of the quantitative gas/oil ratio data for many other Azerbaijanian and world basins, an attempt is made to assess the reserves in the prospects. The total recoverable oil reserves in Azerbaijan are estimated at 3.5 bln tons, of which slightly above 2 bln tons have already been extracted. Based on the statistically estimated ratio between the volumes of gas and oil in various basins of the world, including Azerbaijan, the total possible natural gas reserves in Azerbaijan are estimated at about 4 trillion m3 . This is in agreement with the other available estimates. Of this volume of natural gas, 0.85 trillion m3 has already been extracted, and the approved geological reserves are estimated at 2.55 trillion m3 . Almost 83% of the extracted natural gas belonged to offshore fields. This trend will continue in the future, and, moreover, will be strengthened due to large volumes of gas condensate accumulations in the deepwater part of the basin. In this part of the basin, the most attractive prospects are Mashal, Shafag, and Israfil Huseynov, total reserves of which are expected at 0.6 trillion m3 of natural gas.

The current state and 125 kyr history of permafrost on the Kara Sea shelf: modeling constraints

The evolution of permafrost on the Kara shelf is reconstructed for the past 125 kyr. The work includes zoning of the shelf according to geological history; compiling sea level and ground temperature scenarios within the distinguished zones; and modeling to evaluate the thickness of permafrost and the distribution of frozen, cooled and thawed deposits. Special attention is given to the scenarios of the evolution of ground temperature in key stages of history that determined the current state of the Kara shelf permafrost zone: characterization of the extensiveness and duration of the existence of the sea during stage 3 of the marine oxygen isotope stratigraphy (MIS-3), the spread of glaciation and dammed basins in MIS-2. The present shelf is divided into areas of continuous, discontinuous-to-sporadic and sporadic permafrost. Cooled deposits occur at the western and northwestern water zones and correspond to areas of MIS-2 glaciation. Permafrost occurs in the periglacial domain that is within a zone of modern sea depth from 0 to 100 m, adjacent to the continent. The distribution of permafrost is mostly sporadic in the southwest of this zone, while it is mostly continuous in the northeast. The thickness of permafrost does not exceed 100 m in the southeast and ranges from 100 to 300 m in the northeast. Thawed deposits are confined to the estuaries of large rivers and the deepwater part of the St. Anna trench. The modeling results are correlated to the available field data and are presented as a geocryological map. The formation of frozen, cooled and thawed deposits of the region is inferred to depend on the spread of ice sheets, sea level, and duration of shelf freezing and thawing periods.

New exploration opportunities along Australia's southern margin

The 2012 Australian offshore acreage release includes exploration areas in four southern margin basins. Three large Release Areas in the frontier Ceduna Sub-basin lie adjacent to four exploration permits granted in 2011. The petroleum prospectivity of the Ceduna Sub-basin is controlled by the distribution of Upper Cretaceous marine and deltaic facies and a structural framework established by Cenomanian growth faulting. These Release Areas offer a range of plays charged by Cretaceous marine and coaly source rocks and Jurassic lacustrine sediments. In the westernmost part of the gas-producing Otway Basin, a large Release Area offers numerous opportunities to test existing and new play concepts in underexplored areas beyond the continental shelf. Gas and oil shows in the eastern part of the Release Area confirm the presence of at least two working petroleum systems. In the eastern Otway Basin, several Release Areas are offered in shallow water on the eastern flank of the highly prospective Shipwreck Trough and provide untested targets along the eastern basin margin southward into Tasmanian waters. To the south, a large Release Area in the frontier Sorell Basin provides the opportunity to explore a range of untested targets in depocentres that formed along the western Tasmanian transform continental margin. Two Release Areas offer exploration potential in the under-explored eastern deepwater part of the Gippsland Basin. Geological control is provided by several successful wells indicating the presence of both gas and liquids in the northern area, while the southern area represents the remaining frontier of the basin