1112 



EXPLORATION GEOPHYSICS 



RADIOACTIVITY LOG 

 GAMMA RAY CURVE NEUTRON CURVE 



RADIOACTIVITY INCREASES RADIOACTIVITY INCREASES 



INDICATES POSSIBLE 

 POROUS ZONE 



Fig. 697. — Radioactivity log. (Courtesy of Lane- 

 Wells Company.) 



RADIOACTIVITY LOG 

 GAMMA RAY CURVE NEUTRON CURVE 

 1800 RADIOACTIVITY INCREASES, 



6AMMA RAY AND NEUTRON 

 CURVES ON A WELL IN THE 

 SALT FLAT FIELD IN TEXAS 



Fig. 698. 

 (Courtesy of Lane-Wells Company.) 



