Oil-Gas Potential of Pechora Sea
Internet Geology News Letter No. 37, March 20, 2000
The Pechora Sea is the southeastern part of the Barents Sea and
is tectonically the northern part of the Pechora platform. The onshore
tectonic features extend northward offshore to the Kurentsov step,
where the Paleozoics plunge abruptly to depths of 10-12 km in the
South Barents depression.
The entire Pechora Sea has been covered by seismic surveys
in various detail, and exploration has been carried out in six areas.
These are all in the south, where the Paleozoics are at comparatively
shallow depth. Since direct geological information is limited, the
stratigraphy for these areas is synthesized from the surrounding
onshore areas.
No Cambrian rocks have been found in the onshore part of the
Pechora platform, but based on outcrops on Novaya Zemkya it is
possible that Cambrian shale, quartzite, and carbonates up to 2000
m thick are present on the shelf of the Pechora Sea.
The extensive occurrence of Silurian-Ordovician Seismic Horizon
IV in the Pechora Sea suggests strongly the presence of Ordovician
rocks in the study area.
Marine seismic surveys show Silurian rocks some 400-500 m
thick in the west to 1500-2000 m in the east. Clastics predominate in
the west with increasing carbonates with possible reefs in the east.
Both Lower and Middle Devonian are largely clastic on the west,
passing eastward into carbonates. The Upper Devonian consists of
lower Frasnian clastics and basalt, middle Frasnian Domanik clastic and carbonate rock, upper Frasnian carbonate with reefs, and Famennian
carbonates. Thickness of the Devonian is 500-600 m on the west to
1000-1500 m on the east.
The Carboniferous is largely carbonate ranging in thickness from
150 m on the west to 300-400 m on the east.
The Lower Permian is largely carbonate but passes upward into
clastics with total thickness of 250-550 m. The Upper Permian
consists of redbeds 200-600 m on the west to 2000 m on the east.
The Triassic consists of clastics 700-1200 m thick on the west to
3000 m on the east and north. The Jurassic is near-shore marine sands
and clays and lake-swamp facies 100-200 m thick. The Lower Cretaceous
is sand-clay 200-350 m thick, and the Neogene is clastic 70-250 m thick.
Rather well defined structural features of the Pechora Sea include ten downwarps, eight swells, and two monoclines. These are plotted on
a map in Petroleum Geology, vol. 34, no. 2, 2000, where they are
described individually.
Five oil and gas fields have now been discovered in the Pechora Sea:
Severo-Gulyayev oil-gas-condensate, Pamor gas, and Prirazlom, Varandey, and Medyn oil fields. Four of these are classidied as large. Of the 54 local structures presently known in Pechora Sea, 18 are ready for drilling.
Initial recoverable resources of the shelf of Pechora Sea are assessed at 4.9 billion tons of oil equivalent (34.3 BBOE), of which oil and condensate account for 2.2 billion tons (15.4 BBO). From Letavin and Kurenkov, 1999; digested in Petroleum Geology, vol. 34, no. 2, 2000.
Copyright 2000 James Clarke. You are encouraged to print out this News Letter and to forward it to others. Earlier News Letters are available at:
http://geocities.com/internetgeology/
