Мурманская МИЛЯ. 2018 г. №4.

EXPLORATIONS on the pre-Quaternary formations map have been updated. Seismoacoustic sections allowed marking a series of sequences in the Quaternary formations and the bottom sampling data allowed creating a lithologi- cal map of the studied water area bottom which was not available in the previous edi­ tion. On the whole, deep structure, magma- tism, structural and formational consistence, Quaternary and modern deposits structure, environment state and resources prospects of the explored area are highlighted at the new level of study. The leading role of the Tarian sequence granitoids for the tin mineralization has been confirmed. The main commercial tin content refers to the large polygenetic deposit of the Paleocene to Holocene age associated with the areas of persistent high zone and alter­ nating movements. Potential coal fields are associated with the Balyktakh sequence in the trough core. The potential geological oil and gas resources are 1,149.75 million TOE, recoverable resources volume is 838.94 mil­ lion TOE. It is recommended to perform regional seismic exploration in the western Laptev Sea part of sheets explored by the widely spaced seismic grid. The Omoloy downfolds zone and the East Laptev structural zone can be explored in order to update the structure of the Cretaceous to Cenozoic plate cov­ er, physiography and inner structure of the folded basement of the western slope of the New Siberian system of grabens and horsts. The most prospective area for oil and gas field development within sheets S-53, 54 is the north-western map section: the junc­ tion of the Stolbovsky horst northern part and Belkovsko-Svyatonossky and Zapadno- Belkovsky grabens where a large pervasive high zone is located. This section is adjacent to the Anisinsko-Novosibirsky license block of Rosneft and may be of interest to subsoil users. Sheet S-38 of the State Geological Map substantially updated and supplemented by raw data compared to the previous edition has been created. According to the data of regional seismic survey performed in 2005 - 2014 there were created the structural maps of sedimentary cover bottom and main reflectors marking the Caledonian un­ conformity in the late Silurian, pre-Frasnian perturbation, the surface of the low Permian carbonate deposits, the Permian - Triassic discontinuity, the Jurassic bottom and the roof of the upper Jurassic to lower Berria- sian black clay. New data of CMP seismic survey with HD upper part of the section also gave an opportunity to update the bounda­ ries of Cretaceous sequences over the area of sheet S-38, to determine the regularity of structure of main oil and gas potential section intervals, namely: the Cretaceous, Jurassic and Triassic formations. The geological map of pre-Quaternary formations compared to the earlier ver­ sion published in 1999 shows that the up­ per Cretaceous deposits are more widely spread over the area. Their proveniance covers a part of the Ludlov ridge and the North Barents syneclise except the South Barents syneclise which is in general a fa­ vourable aspect when estimating oil-and- gas prospects especially Cretaceous po­ tential oil-and-gas sequence. In geological sections the Triassic and Jurassic deposits are dissected more in detail. The variation of seismic thickness in different structural formational zones and supposed lithologi- cal composition of rocks are specified in the legend. Updated features of the Earth’s crust deep structure and tectonic struc­ ture of the area are given in correspondent schemes provided with a series of structural plans on main unconformities in the sedi­ mentary cover. On the updated geological and struc­ tural basis the position of oil and gas re­ gions have been updated, potential oil-and- gas accumulation zones have been marked, namely: the Nadezhdinsko-Tulomskaya zone of potential oil-and-gas accumulation in the South Barents petroleum region; the Med- vezhinskaya and Luninskaya zones within the Shtockman-Luninskaya petroleum region. An assessment of potential hydrocarbon resources including localized resources of anticline structures, their prospective rank­ ing have been made. Main prospects are associated with the Jurassic, Triassic and partially (in the Svalbard potential oil-and- gas region) with the Permian terrigenous and the upper Devonian to lower Permian oil-and-gas sequences. The forecast resources of the sedimen­ tary cover within the limits of sheet S-38 ac­ count for 6,997.27 million TOE (geological). 542.96 million ton out of them fall to the share of oil and 110.13 million ton - to the share of condensate. Recoverable forecast resources may account for 6,595.17 million TOE (oil - 191.01 mln t, condensate - 88.86 mln t). Localized forecast resources are estimated at 1,476.05 million TOE, 88.51 MURMANSK MILE • 4-2018