LUMINESCENCE LOGGING 



323 



proposed that this can he done by studying the spectral characteristics of 

 the luminescent radiation. In order to check this, the spectral characteris- 

 tics of petroleum and petroleum products were determined and are shown 

 in Figs. 7 and 8. 



As can he seen, the principal petroleum products, which can enter the 

 drilling fluid (kd^ricating materials — motor oil, solidol, machine oil, graph- 

 ite grease), have a sharp maximum in the left-hand part of the spectral 

 characteristic (wavelength about 480 m^), which differs markedly from 

 the spectral luminescence characteristics of heavy petroleums. 



'O 



/ 



WOODS 



HOLE, 



MASS. 



600 



Fig. 7. Luminescence spectra. 1 — motor oil No. 13; 2 — motor oil No. 6; 3 — macliine 

 oil; 4- — solidol; 5 — graphite grease; 6 — fuel oil No. 350, 



Figure 8 shows the spectral characteristics of luminescence from a clay 

 suspension, to which petroleum and lubricating materials had been added. 

 It can be seen that the spectral characteristics of the luminescence from the 

 clay suspension correspond to the spectral characteristics of bitumen contained 

 in the clay suspension. When motor oil is added to the clay suspension, the 

 maximum shifts to the left and, as the concentration of motor oil is increased, 

 approaches more and more closely to the motor oil characteristic. 



Thus, in the case when the explored petroleum is heavy and contains 

 a fair amount of resinous components, it can be distinguished from lubri- 



