Study of metals in asphaltene fraction of crude oil and bitumen from source rocks of Cambay Basin, India

摘要

Major and trace elements like calcium, magnesium, sodium, potassium, copper, iron, zinc, cobalt and nickel were studied in asphaltene fraction of crude oil and chloroform extracted organic matter extracted from potential source rocks of Cambay Basin, India. Concentration of elements in asphaltene varies from one producing horizon to another and from one field to another. Nickel concentration shows decreasing trend in asphaltene with depth, whereas it should be constant in asphaltenes separated from oils of same source and maturity. This indicates that active exchange of nickel takes place during migration of oil and direction of increase in nickel concentration in asphaltene may be helpful in determining direction of migration. The difference in correlations of elements in EOM and asphaltene indicates that they are associated in different organo-metallic complexes in asphaltene and EOM.