DRILLING SUPER-DEEP HOLES IN THE CENTRAL PART OF THE NEAR-CASPIAN DEPRESSION

The Near-Caspian Depression is a deeply subsided southeastern block of the Russian platform consisting of Paleozoic, Mesozoic, and Cenozoic sedimentary rocks as thick as 15, 000 m. Most geologists hold, under the salt complex, there are pre-Kungurian Paleozoic sediments of platform type composing upwarpings and downwarpings (anteclises and syneclises). The'outlook for, oil and gas in the Near-Caspian is very good; it is especially true of the complex overlying the salt and the Emba district where oil was found; the Paleozoic deposits below the salt are also promising.

Prospecting for oil and gas here is possible only with the use of super-deep drilling, and of special importance is drilling of two test super-deep boreholes (to 7, 000 m). First of all it is necessary to select such areas within which deposits below the salt could be struck at a depth not more than 5 or 6 km and where a Paleozoic section from 1, 000 to 2, 000 meters thick can be found. It is necessary as well to carry out seismic surveys within the Ural-Volga Depression and the eastern monocline in order, to find a most favorable environment. Super-deep drilling is part of a program including base and parameter borehole drilling and regional seismic profiles.—Auth. English summ.