322 



T. V. Shcherbakova 



It can be seen that, by means of the apparatus described above, it is 

 possible to detect petroleum in the clay suspension down to a content of 

 0.5-1 cm^ per litre, i.e. approximately as much as can be detected by visual 

 examination of clay suspension samples in ultra-violet light in the lumi- 

 noscope. 



150 



iQG 



^ 



50 



2 / 



^--•'■■4 



10 20 30 



C. cm^/L 



Fig. 6. Intensity of luminescence of petroleum in drilling fluid as a fmiction of 

 concentration, 1 — petroleum with intensity Iqll^ = 30.0, dark clay suspension; 

 2 — ^petroleum with intensity Iqll^ = 2.62, same suspension; 3 — ^petroleum with inten- 

 sity IgjI^Q = 1.74, light clay suspension; 4 — the same petroleum, dark clay suspension. 



For the concenlrations of petroleum in clay suspensions which we have 

 examined, the intensity of the luminescent emission is proportional to the 

 amount of petroleum and no concentration extinction has been noticed. 

 The coefficient of proportionality depends strongly on the nature of the 

 petroleum and the clay suspension. However, it can be expected that, for 

 a given type of clay suspension and petroleum, it is possible to obtain a quan- 

 titative estimation of the amount of petroleum in the clay suspension 

 from the instrument readings. 



SPECTRAL CHARACTERISTICS OF PETROLEUM AND PETROLEUiM PRODUCTS 



In luminescence logging it becomes necessary to differentiate between 

 the luminescence of explored petroleum and. the luminescence of petroleum 

 products that have entered the drilling fluid in the process of drilling. It is 



