178 O. H. GISH 
from the data of resistivity surveys, taken along with other informa 
tion which can be supplied by the geologist and the petroleum engi- 
neer, the approximate depth and the features of the more general 
structure associated with petroleum resources. 
Reports of actual tests seem to bear this out, perhaps rather tco 
well in some cases. This applies especially to some recent tests which 
came to attention! as this conclusion was being written. These con- 
sisted of the correlation of hundreds of drill-hole records with results 
of resistivity surveys made by five different parties in as many differ- 
ent oil fields in Russia. According to the abstracts, one of the articles 
contains the conclusion that “‘more tests are required to draw defi- 
nite conclusions on the degree of usefulness”’ of this electric method. 
This leaves one uninformed as to whether or not any indication that 
the method may prove useful was found. However, there is no am- 
biguity in the four other conclusions, which run as follows: “This 
method is of great importance in geological interpretation of the sub- 
soil and should be used on a large scale’’; ““whether the mechanical 
coring can entirely be substituted by this method or not can not be 
definitely decided at present.’’ One in which 180 drill-holes were in- 
vestigated concludes that this ‘‘must be recognized as one of the most 
useful and necessary methods of determining the correlations in the 
stratigraphical conditions of oil deposits.” In what appears to be the 
most extensive of the five investigations 220 drill holes were covered. 
In the report of this it is concluded that “‘the great advantage of 
electrical coring is established.” The full reports may restrict some of 
these conclusions more than is indicated in the abstracts. 
It is perhaps utopian to wish that these investigations had also 
included surveys by the other outstanding geophysical methods. An 
investigation of such scope should have considerably lessened the 
element of guesswork which is involved in making a choice from the 
several available methods. The writer is not impelled to venture such 
a guess here; he is, however, convinced that some geoelectric methods 
will in due time be accepted as useful aids in the search for oil. 
1 Geophys. Abstr., No. 37 (1932), pp. 450-53. 
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