Petroleum
Resource Potential of the
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
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
AAPG Search and Discover Article #90063©2007 AAPG Annual Convention, Long Beach, California