678 



Subsurface Geologic Methods 



ure 366. In the three illustrations of this figure, the electrode assembly 

 is shown completely immersed in oil, immersed half in acid and half in 

 oil, and completely immersed in acid. Each of the illustrations shows the 

 electrode assembly connected with a battery (B) and an ammeter (A) and 



Single Conductor 

 Cable 



Fluid Passages 



insulated 

 Conductors' 



TafI Pipe 



Tubing 



eating Ring 

 Seating Nipple 



Fluid Contacts, 

 Insulated from 

 Body of Pilot 



Collar 



Figure 365. Diagram of electrode. 



the ammeter readings that can be expected under each of the three con- 

 ditions that are possible at the bottom of the hole during acid treatment. 



In the left-hand illustration of figure 366, only oil is in contact with 

 the assembly, and, as oil is a nonconductor, the electric circuit between 

 the electrode and the body of the assembly is not completed. No current 

 flows in the circuit and the ammeter registers zero. 



In the center illustration of figure 366, acid is in contact with the 



