THE LOOP METHOD IN EXPLORING BURIED STRUCTURES 265 



drilling and, with the established correspondence of deep tectonics to the 

 structure of the upper levels of the section, provide a basis for the laying of 

 deep exploratory wells. By showing the tectonics of the studied area, the 

 results of the loop investigations condition the further geological work, 

 which ensures rational use of materials and time in surveys and explora- 

 tions of petroleum deposits. 



However, the underestimation of the possibilities of this method, and 

 sometimes the simple lack of inclination to sort out the results of previous 

 studies meant that areas covered by detailed surveys by the loop method 

 were overlapped by detailed geological surveys and cartographic drilling 

 which increased the expense of the exploration, especially bearing in uiind 

 the difficulties of the geological survey under the conditions of the muddy 

 Maikop formations. 



For example, at the Uzunlar dome of the Kerch peninsula a satisfactory 

 solution of the problems facing the geological survey party was achieved 

 by carrying out a large volume of work. On the surveyed area of 150 km^, 

 606 prospecting pits were dug to an average depth of 3.4 m, 384 wells -were 

 drilled by hand to an average depth of 12.2 m, 36 ditches were dug and 

 270 exposures were described. The field work took 9 months (^°). 



The survey of this area by the loop method took 30 days. During this 

 time, about 1300 loop vectors were measured with an octagonal arrange- 

 ment of diameter d = 100 m. 



As already mentioned, the results of all these investigations provided the 

 same structural pattern of the studied area. However, owing to the dense 

 network of the observations the pattern is more firmly based on the data 

 of the loop method. 



To compare the economic and production effectiveness of geological 

 surveying and geophysical work by the loop method another example can 

 be chosen by quoting the survey on the Marforov area (the south-western 

 plain of the Kerch peninsula). To study the structure of this area of 56 m^, 

 133 prospecting pits were dug to an average depth of 3.5 m, 216 wells were 

 hand -drilled with an average depth of 15 m, and 150 natural exposvires 

 were described. The field period lasted 10 months (^^) and the work cost 

 183,000 roubles. 



The survey of this region with the loop method lasted 12 days, 450 loop 

 vectors being measured. The cost of the work was about 30,000 roubles. 

 The results of the surveys are identical. To illustrate the efficiency of 

 a field group using the loop method we give certain figures from the accounts 

 of the group 13/50 of the department Krasnodarneftegeofizika working 

 in 1950 in the Kerch and Taman peninsulas (^^). 



