THE PERMEABILITY OF OIL-BEARING STRATA 



363 



at their extreme parts cast doubts on their vahdity. According to the Morozov's 

 curves, in a low porosity rock in a number of cases there will be very small 

 values for the interstitial water saturation and very large values for the 

 coefficient of increase in resistance; for example, for m = 0.1 and K = 10 

 milhdarcies we should have Q pn 10 and an interstitial water saturation of 

 only 10%. However, this is not very probable. 



Sultan ov and Dobrynin (^'*) propose for the determination of permeability 

 of the Devonian sandstone from the specific resistance the use of the relation- 

 ship between the coefficient of increase in resistance and the reservoir 

 properties of the strata, represented by continuous curves on Fig. 3. 



100 



Fig. 3. Curves for the dependence of the coefficient of increase in resistance Q on 

 the permeability Kp^^ for sandstones of the Povolzh'yc Paleozoic. Cnrve symbols- 

 porosity m. Dashed curves — according to MoROZOvd^, Fig. 6). continuous curves- 

 according to SuLTANOv and Dobrynin'^*). 



Table 2 gives the mean and mean square errors for individual 

 determinations of permeability by specific resistance using the Sultan ov- 

 DoBRYNiN curves. The coefficient of increase in resistance was represented 

 by those values for which determinations were made of the permeability 

 according to the Dolina curve (corrected). The values for the coefficient 

 of increase in resistance were obtained from the value of resistance of the 

 stratum, corrected by the use of the porosity data of a stratum with 100% 

 filling of its pores with water. 



