An investigation has been made of the distribution of rhenium in 50 sp
ecimens of oil and bituminous Kazakhstan rock as a function of the dep
th of occurrence and the organic content of the oil and bituminous roc
k. It was established that rhenium is chiefly concentrated in paraffin
ic-naphthenic hydrocarbons, an increase in the content of which has a
corresponding effect on the rhenium concentration in the bitumen.