ELECTRICAL PROBING WITH AN APPARATUS IN WATER 183 



layers (pq = 1), the expression (24) for the apparent resistance for an apparatus 

 at the bottom becomes: 



(OO V p OO -1 



(26) 



CALCULATIONS OF THE THEORETICAL CURVES OF SEA PROBING 



With the formulae obtained, a calculation was made for two -layer and 

 three-layer theoretical probe curves with an apparatus at the bottom of the 

 water. 



The theoretical curves for probing with an apparatus both at the surface 

 and at the bottom of the water correspond to the equation 



Q rl Qi Q2 K K 



:f 



where r is the operating distance of the apparatus; 



^1 _ Q2 _ K _ K _ 



Qq Qq K K 



are the parameters of the geoelectrical section. 



The theoretical probing curves are drawn on a double logarithmic 



scale as the values for the dependence of— on _ - , the remaining para- 

 mo ^0 

 meters {jx-^, [x^-t •••' '^i' ^2~-") ^^^ eia.c\\ curve are constant values. The para- 

 meters of the calculated curves were selected to correspond with the para- 

 meters of three-layer theoretical curves of the Schlumberger charts and 

 curves calculated at the GSGT, taking into account the features of the 

 section, the upper layer of which is the sea-water. 



For a two-layer section the following values were selected for [x^: 11/9, 

 3/2, 13/7, 7/3, 3, 4, 17/3, 7, 9, 19, 39, 99 and oo. The curves with [jl < 1 

 were not calculated since in practice the water always has a lower resistance 

 than that of the underlying medium. 



For the three-layer section the following parameters were chosen: 



