New Geophysical Data on Sedimentary Basins in Siberian Arctic

Alexander V. Grevtsev, Natalia A. Petrovskaya, and Alexander V. Savitsky
DMNG JSC, Yuzhno-Sakhalinsk, Russian Federation.

In 2010, DMNG acquired integrated geophysical survey in the Siberian Arctic using a long streamer (8000 m), a high capacity airgun source (5,000 cu in) and a record length of up to 12 seconds. This allowed for recording consistent reflections at depths of up to 30 km. A number of new geological phenomena, which are of great importance for understanding of the regional geology and tectonics as well as for hydrocarbon resource evaluation in Novosibirsky and North Chukchi basins, were identified.
Novosibirsky Basin:

Sedimentary cover of significant (more than 20 km) thickness was distinguished in the south part of the East Siberian Sea for the first time. Maximum depth of the acoustic basement is 9 - 9.2 seconds. Previously the basement surface was marked by the dynamically apparent boundary traced at the top of the sedimentary cover at 0,5-2,0 seconds.

The acquired data allow to reconsider the current opinions about Cretaceous-Cenozoic age of the sedimentary cover of Novosibirsky basin, which very likely contains deposits from Paleozoic to Upper Jurassic - age equivalents of the Ellesmerian and possibly the upper part of the Franklinian sequences.

Presence of diapirs in the sedimentary cover was confirmed; in the middle part of the section the diapirs form diapiric folds with crests recorded at depths of 4-6 seconds.

In terms of tectonics, location of the south-east centroclinal closure of Novosibirsky Trough was identified.

Geophysical indicators of section productivity were distinguished. They were most pronounced in the Dreamhead Rift area.

North Chukchi basin:
Well stratified sedimentary section is tracked to the depths more than 9 seconds.
In the middle part of the section, oblique (inclined bedding) seismic facies are distinguished.
A number of anomalies, which evidence the presence of hydrocarbons in sedimentary cover, were identified within several major structures.
In-depth and comprehensive interpretation of the acquired data is yet to be made. However it is safe to say now that the data will be most helpful for better understanding of both the Siberian Arctic geological history and its hydrocarbon potential.

AAPG Search and Discovery Article #90130©2011 3P Arctic, The Polar Petroleum Potential Conference & Exhibition, Halifax, Nova Scotia, Canada, 30 August-2 September, 2011.