Hydrocarbons Exploration in East Siberia Southern Basins
RESNICK, VICTOR S., Petroconsultants Inc., Houston, TX
The vast Lena-Tunguska province in the heart of Siberia is among the world's largest and least explored frontier basins. Some encouraging exploration has nevertheless been carried out in the four southern subbasins: PrePatom (PreBaykal) trough, Nepa-Botuobin anticlise, PreSayan-Yenisey basin, and Angara-Lena terrace.
Source rocks are essentially Proterozoic, but younger sediments may contribute about 10% of the region's oil potential. Riphean-Cambrian subsalt reservoirs contribute more than 90% of the hydrocarbons discovered, whereas Cambrian salt provides the most common regional seals.
The main hydrocarbon lateral migration occurred in Vendian-Cambrian. Traps include clastic wedging out along favorable structures and carbonate reef-like buildups. Many traps were tranformed or destroyed by the late Paleozoic-early Mesozoic volcanic activity, whereas Hercynian overthrust tectonics developed new traps in the PrePatom trough.
About 30 discoveries, mainly gas and condensates, have been made in the area, but operations are hampered by poor logistics and limited infrastructure.
AAPG Search and Discovery Article #91007© 1991 AAPG International Conference, London, England, September 29-October 2, 1991 (2009)