NEW METHODS OF ELECTRICAL EXPLORATION IN SIBERIA 221 



the supply sources) with a liigh-vokage mput, its circuit being similar to 

 that of the EShO-56 oscillograph. 



2. An oscillograph with a spring motor (weighing not more than 8 kg 

 together with the filament batteries of the illuminator lamp. 



3. An RPMS radio station with a power pack, into which is also assembled 

 the TV-6 tele-switch used in transmitting and receiving the time signals 

 by radio (tw^o units weighing 11 kg each). In the tele-switch there is introduced 

 an interference stable system, which limits the interference level. 

 Consequently, even with a high level of interference, the TV-6 does not give 

 false time signals. 



4. Non -polarizing portable electrodes; 



5. Two cable reels (weighing 2 kg each). 



The use of the amplifier makes it possible to record also telluric current 

 variations, which due to the insufficient amplitude would be considered 

 unworkable when using an EPO-4 oscillograph. 



The whole of the apparatus is fixed in the body of the station but if the 

 vehicle is unable to continue, since the arrangement is sufficiently portable 

 the apparatus can be removed in 2-3 min and carried by three of the field - 

 party members to the observation point. 



CONCLUSIONS 



The work of the VNII Geofizika has shown the effectiveness of new electrical 

 survey methods under conditions prevalent in the Western Siberian Lowlands. 



These methods should find applications in solving regional and survey 

 problems of geophysical investigations for petroleum and gas. 



At the present stage the exploratory observations on telluric currents are 

 best used to solve problems of a regional character (separating out large 

 depressions and culminations, and also detecting upfolds of the second 

 order) in conjunction with gravimetric and aeromagnetic work in tectonic 

 surveys of the Western Siberian territory. 



The most effective results can be obtained on a scale of 1:1,000,000 with 

 a net work density of 1 point per 100 km^. It is desirable also to carry out 

 separate length profiles along rivers. With a favourable geoelectrical cross- 

 section the telluric current method can also be used to survey local upfolds. 



The two-way electrical probing should preferably be directed towards 

 the solution of survey and exploration problems, and also for setting up 

 a basic network for the telluric current method in regional studies. 



The results of experimental work carried out in the Western Siberian 

 Lowlands open up possibilities for a more extensive use of electrical prospect- 



