The structural features of the subsalt carbonate complex in Khoronohskoye license area, the Republic of Sakha (Yakutia)

UDK: 553.98.001
DOI: 10.24887/0028-2448-2018-2-26-29
Key words: pre-salt complex, tectonic deformation of the ramps of detachment, ostantsovy deposits, zones of crushing
Authors: E.P. Kropotova (Tyumen Branch of SurgutNIPIneft, RF, Tyumen), M.G. Lebedeva (Tyumen Branch of SurgutNIPIneft, RF, Tyumen), T.A. Korovina (Tyumen Branch of SurgutNIPIneft, RF, Tyumen)

Khoronohskoye license area located within regional zones of the southern Siberian platform has a very complex structure of the sedimentary cover. It is a division of auto - and allochthonous parts. In addition to faulting (microgravity, rift stage, faults, etc.) in the thickness of the subsalt carbonate complex with traces of horizontal formation-thrust deformations that lead to a two-fold repetition in the context of some horizons.

Historically, the region of South-Western Yakutia has developed by type of collision passive continental margin. The development took place in four stages, which formed two tectonic complexes. The lower complex (autochthonous) has a block character and it consisted of the rocks of Riphean and Vendian-Cambrian age. The upper complex (allochthon) is a series of tectonic slices, thrust over the platform slope, with an age of the Upper Vendian - Lower Cambrian. The territory with the likes of autochthonous and allochthonous occurrence of the horizon, installed on Khoronohskoye license area. Here in the North-East can be traced long thrust area (thrust), confirmed the drilling data and seismic profiles. The ledge in the relief from Bukskaya suite hindered the promotion of the allochthon in the North-West, which has led to the emergence here of detachment ramp of the allochthon is an abrupt transition of the Vendian salts (Torsalskya bundle) to the level of the Cambrian salts (Ureginskya suite). This has led to the reduction of the thickness Torsalskya salts on the elevations to a complete wedging out, and blown - in depression.

Faults of autochthonous determine the prerequisites for the persistence outlier hydrocarbon deposits. In the sediments of the allochthon hydrocarbon deposits can also be, as evidenced by signs of oil saturation in cores and inflows of hydrocarbons on the test results of some wells. With the forecast promising areas special attention should be paid to the sediments of the allochthon, the prospect of which is associated not only with the processes of thrusting, contributing to the emergence of new structures, fractured zones, fluid migration, but also with the availability of depths for drilling.

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