--> Abstract: Petroleum Resource Potential of the Laptev Sea Shelf, Russia; #90063 (2007)

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Petroleum Resource Potential of the Laptev Sea Shelf, Russia

 

Klett, T. R.1, F. Persits1, G.F. Ulmishek2 (1) U.S. Geological Survey, Denver, CO (2) Direct Petroleum Exploration, Inc, Denver, CO

 

The Laptev Sea Shelf is located in the Russian portion of the Arctic Ocean. It is an area of extensional tectonics initially formed in Late Cretaceous (?)-Paleocene time. The Ust' Lena Rift system occupies the western part of the province and the Laptev Horst the eastern part.

 

Most of the shelf and slope are underlain by crystalline rocks of the Siberian platform. A deformed pre-rift sedimentary section consists of mainly upper Proterozoic-Devonian carbonates and Carboniferous-Lower Cretaceous siliciclastics. Syn-rift rocks of the Laptev Sea Shelf are interpreted to consist of Upper Cretaceous (?)-Tertiary siliciclastics. The acoustic basement appears to be an erosional unconformity developed during Late Cretaceous to early Paleocene time and traced to depths as much as 13 kilometers.

Published analyses of natural gas collected from near-bottom waters and sediments indicate the presence of mature oil-prone marine source rocks, presumably of Paleogene age. Upper Jurassic organic-rich mudstone may be another important source rock. Rapid deposition of thick Tertiary sediments in combination with higher heat flows typical of rift basins thermally matured the source rocks.

 

Traps for petroleum accumulation could include rotated fault blocks, horsts, and pinchouts of siliciclastic rocks within grabens, and anticlinal traps in the pre-rift section. Most traps were probably formed prior to petroleum generation and expulsion. Petroleum could have migrated vertically along faults, as evidenced by possible natural gas chimneys, and laterally into juxtaposed reservoirs along fault displacements.

Major syn-rift reservoir rocks are likely to be shelf and slope siliciclastic strata deposited by the paleo- and present-day Lena River. Pre-rift reservoir rocks may include upper Paleozoic-Mesozoic paralic and marine siliciclastics and Paleozoic carbonates.

 

AAPG Search and Discover Article #90063©2007 AAPG Annual Convention, Long Beach, California