Oil-oil correlation by FTIR spectroscopy of asphaltene samples

Abstract

In this paper, a new technique with easy interpretation, low cost, and reliable results is presented for oil-oil correlation purpose. In this technique, the structural characterization of asphaltene, because of its structural similarity with kerogene and resistance to secondary processes (e.g., migration, biodegradation, thermal maturity, and so on), was considered as a correlation parameter and asphaltenes structure similarity in different oil samples is the basis of geochemical correlation. FTIR spectroscopy was applied to detect and compare asphaltene structures with each other. The four oil samples from different oil fields in the Iranian sector of the Persian Gulf were investigated by FTIR spectroscopy and introduced indexes that represent structural characteristic of asphaltenes enabled us to perform geochemical correlation. To validation of this technique, the other common geochemical techniques (e.g., stable carbon isotope and biomarkers) were applied to geochemical correlation. These techniques completely supported and complemented the results of the asphaltene FTIR spectroscopy technique. The results of these three techniques show genetic relationships among these 4 oil samples and indicated that these oil samples belong to two distinct oil families. The First oil family originated from carbonate rich source rock and the second oil family was sourced from calcareous shale source rock.