East Siberian Sea runoff into the East Siberian Sea is relatively small at about 250 km/year that makes only 10% of the total runoff in all the Arctic seas of Russia. The largest contribution is from the Kolyma River at 132 km, followed by the Indigirka River at 59 km. Most runoff (90%) occurs in summer; it is concentrated near the coast, owing to the weak river currents, and therefore does not significantly affect the sea hydrology. The water exchange between the neighboring seas is as follows. The annual outflow to the Laptev Sea, Chukchi Sea and Arctic Ocean is 3,240, 6,600 and
West Siberian petroleum basin wells have been drilled offshore. Undiscovered gas potential of both assessment units is very high. West Siberian petroleum basin The West Siberian petroleum basin (variously known as the West Siberian hydrocarbon province, Western Siberian oil basin, etc.) is the largest hydrocarbon (petroleum and natural gas) basin in the world covering an area of about 2.2 million km. Geographically it corresponds to the West Siberian plain. From continental West Siberia, it extends into the Kara Sea as the East-Prinovozemelsky field. The public domain U.S. Geological Survey Bulletin 2201-G describes the basin as follows. The basin occupies a swampy plain between the