485 
The continental crust is separated from the oceanic crust by 
geosynclinal deeps associated with island arcs. 
The Bering Sea shelf adjoing the Soviet Union is folded into deep 
depressions that contain thick deposits of Mesozoic and Cenozoic 
sediments. The largest of these depressions, the Anadyr basin, is con- 
sidered to have good offshore hydrocarbon potential, for gas and 
condensate deposits have been discovered in Cenozoic sandstones in 
onshore portions of the structure. There are other depressions in 
the Bering Sea shelf in which hydrocarbons also may be present. 
Another prospect is the offshore extension of the eastern Kamchatka 
basin where near-commercial oil has been discovered onshore in the 
same structural unit.” 
Approximately half of the Sea of Okhotsk and the Japan Sea is 
considered prospective in Tertiary and also possibly in Cretaceous 
strata. Prospects are especially favorable on and adjacent to Sakhalin 
Island and in the western Kamchatka shelf. Large depressions are 
present containing 5 to 6 kilometers of sedimentary rock. Commercial 
oil and gas deposits have been discovered by onshore directional 
drilling into the Odoptu-Tossin uplift on the northern Sakhalin shelf 
and gas has been found in two onshore wells in the Aniva depression 
to the south.'* 
CONCLUSION 
Approximately 75 percent of the extensive Soviet continental shelf 
has good oil and gas potential.!*> The prospective areas are associated 
with such adjacent land features as platform basins and troughs, fore- 
deeps, and geosynclinal depressions. Mesozoic rocks are considered 
ae prime hydrocarbon prospects with the older Paleozoic rocks secon- 
ary. 
More than 70 percent of the prospective shelf area is in the Arctic, 
where deep depressions containing great thicknesses of sedimentary 
rocks are present on the shelves and are connected closely with proven 
oil and gas provinces onshore.'® These shelf areas, however, will 
require further study. 
Climate and geography, as well as geology, favor continued develop- 
ment of the Caspian region. In the Far East, the Sakhalin shelf and 
Anadyr basin should be of primary interest because of the discoveries 
already made there. 
The U.S. Geological Survey estimates potential U.S.S.R. offshore 
gas reserves at 100 to 1,000 trillion cubic feet and potential U.S.S.R. 
offshore reserves at 100 to 1,000 billion barrels.!” 
CURRENT STATUS OF SOVIET OFFSHORE OIL AND GAS EXPLORATION 
AND PRODUCTION 
A combination of increasing production from frontier areas of the 
U.S.S.R., declining output in the United States, and a world supply 
surplus moved the Soviet Union into the position of the world’s leading 
13 Tbid. 
14 Ibid., pp. 242-243 
'5 Ibid., p. 243. 
16 Tbid. 
™ Frezon, Sherwood E., Summary of 1972 Oil and Gas Statistics for Onshore and Offshore Areas 
of 151 countries. Geological Survey Professional Paper 885, Washington D.C., 1974, p. 141. 
