PROMISING OIL AND GAS COMPLEXES OF PREDVERKHOYANSKАYА OIL AND GAS AREA

Abstract

This article provides information on the main most common and most promising sediment complexes: Riphean, Vendian-Lower Paleozoic and Upper Paleozoic-Mesozoic.
 Riphean deposits within the area under consideration have now been uncovered on the northwestern side of the Vilyui syneclise. Within the southern slope of the Anabar anteclise, the Tankhai and Sokhsolokha structural-formation zones are distinguished.
 Permian deposits are most widely distributed within the Predverkhoyanskiy trough. They were opened by deep drilling wells in the northern part of the Anabar-Lena branch, in the central region (the Kyutingdinsky graben) and in the Aldan branch of the trough.
 The Permian and Lower Triassic deposits adjacent to large gas generation zones of deflections and depressions are characterized by the most favorable conditions for the placement of large oil and gas accumulation zones. In the regional assessment of the conditions for the placement and preservation of large oil and gas accumulation zones, the most favorable conditions are associated with the second hydrogeological floor.
 Seven oil and gas accumulation zones have been identified within the Predverkhoyanskiy pericratonic trough: the Hapchagai-Tomporuk and Loglor-Linden oil and gas accumulation zones are zones with proven industrial gas content. All deposits of the Khapchagai megaval fall into the Vilyuisk zone, due to the presence of horizons with relatively high filtration and capacitance properties in the near-axial part of the hemisyneclise.
 The Predverkhoyanskаyа oil and gas accumulation area combines linear pre-thrust structural traps formed parallel to the face of the structures of the Verkhoyansk folded region advancing on the Mesozoic cover of the platform. Typical traps are pre-thrust and especially sub-thrust anticlines, to a lesser extent closed kinks of layers in the hanging wings of shaft-like up-thrust structures.
 The Kyutingda possible oil and gas accumulation zone is one of the most promising sites for setting up regional exploration. The capacity of sedimentary discharge in the left-bank near-platform part of the Kyutingdinsky graben is estimated at about 5 km. This significantly increases the prospects of oil and gas potential in the north of the Predverkhoyanskiy trough.
 The Prialdanskaya and Prilenskaya possible zones of oil and gas accumulation are located along the platform side of the latitudinal and meridional branches of the Predverkhoyanskiy pericratonic trough, respectively. The prospects for the oil and gas potential of these zones are due, on the one hand, to the development of basal sandstones of the Upper Paleozoic, in which lithologically and stratigraphically shielded traps may be present. On the other hand, numerous bitumen manifestations indicate the intermediate, transit nature of this territory with respect to the migration of hydrocarbons. The terrigenous section of the Upper Paleozoic-Mesozoic deposits of the Prialdanskaya and Prilenskaya is favorable for the accumulation and formation of hydrocarbon traps.