Home – Home – Jornals – Russian Geology and Geophysics 2001 number 4

Support is given to a two-stage model for the salinity of the cover of the Siberian Platform. Cambrian and Devonian halmeic formations are recognized in the section and traced laterally. Lower and Middle Paleozoic halmeic basins were limited by intermediate zones providing a persistent regime of salt accumulation and supply of mother solutions from the vast seas covering the territory of the Patom-Vitim Upland and Upper-Yana region. Parameters are given, and paleostructural conditions of accumulation of these formations are characterized. In some regions and districts of the Lena-Tunguska petroliferous province it has been observed that the industrial production of subsalt reservoirs depends directly on the regional persistence and thickness of the saliferous screen. The largest deposits occur in zones of thick terrigenous sequences overlapped by regional carbonate-saliferous confining beds. Hydrocarbon deposits have not been revealed in the Middle Paleozoic complex yet, though oil, gas, and bitumen occurrences exist there and the geologostructural conditions (reservoirs, brachyanticlinal traps, etc.) are favorable for hydrocarbon accumulation. Taking into account regular relationships in the Vendian-Cambrian complex, we suppose that the Devonian halmeic formation is also appropriate for accumulation and preservation of hydrocarbons in subsalt and intersalt reservoirs.
The recognized structural features of Paleozoic halmeic formations, regional confining beds, permitted us to specify the earlier schemes of petroleum-geological regionalization of the Siberian Platform. In the Vendian-Cambrian complex, the main petroliferous belt is the Nepa-Botuobiyan and Baikit anteclises separated by the Katanga Saddle. In addition, the Berezovo, Kempendyai, and Ygyatta troughs, Suntara uplift, and favorable structures of the central regions of the Angara-Lena trough are estimated as highly promising. The Devonian subsalt and intersalt reservoirs are of greatest practical interest in the favorable zones of the West Vilyui potentially petroliferous region. The Atyyakh, Uchugei, and Kedepchik structural stages are top-priority objects for seismic prospecting and deep drilling there.