376 S. G. KoMAROV and Z. I. Keivsar 



it should be remembered that the methods for determining reservoir properties 

 of the strata from geophysical data, on the whole or for separate stages, 

 are based on a comparison of the geophysical data with the results of core 

 analysis. Thus, from the very start we assume that the true properties of 

 the strata are characterized by the core. 



Evidently the data of core analysis characterize the actual permeabiHty 

 of the stratum sufficiently well and therefore the result of comparing them 

 to the permeability obtained from the specific resistance is very important. 

 This is confirmed by the following: 



(a) the small difference in the values of the mean and mean square errors 

 in determining the permeability from the specific resistance for a different 

 number of cores from the stratum (Table 6); 



(b) the more or less identical mean values for the permeability of the 

 stratum obtained from the data of core analysis and determinations of 

 specific resistance. 



The permeability of a stratum can be determined from the results of 

 logging. It is necessary to compare the results for determinations of permeabiHty 

 from the specific resistance with values for the permeability obtained from 

 the logging data. 



THE BASES OF THE METHOD FOR DETERMINING THE PERMEABILITY FROM 

 THE SPECIFIC RESISTANCE 



Opinion exists that separate strata (for example the Devonian sandstones) 

 have a close (approaching the functional) connection between the interstitial 

 water saturation of the oil-bearing layers and their permeability. A conclusion 

 is therefore drawn suggesting the possibility of the method of determining 

 permeability from the specific resistance (3, 4, 13). However, of the actual 

 data confirming the existence of a close connection of the interstitial water 

 saturation with the permeability, there are only the experimental data of 

 Morozov (see Fig. 10) which, however, are clearly insufficient to prove this 

 affirmation. 



More widespread is the point of view, according to which the interstitial 

 water saturation is a complex function of a number of factors and that therefore 

 a close connection cannot be expected between the interstitial water saturation 

 and permeability. 



Thus, according to Kotyakhov ^^' ^^^^ i^°), although a general tendency 

 is observed of the increase in Avater saturation in the oil-bearing strata with 

 the decrease in their permeability, there is no single and universal connection 

 between the residual water saturation and permeability of the rocks. Further- 



