Significance of thiophenic compounds distribution in correlating crude oils into source related types

ABSTRACT

Gas chromatography and combined gas chromatography/mass spectrometry were used to characterize different thiophenic compounds in representative petroleum from the Gulf of Suez. An evaluation of the distribution patterns of these compounds has been used to infer depositional environment and lithology of crude oil source rock and maturity. Ratios involving dibenzothiophenes (DBT) such as DBT/phenanthrene (Phen) and methyldibenzothiophenes (MDBT)/methylphenanthrenes (MPhen) correlated with other biological markers and were used to classify the oils into different source-related types. Type 1 oils with relatively high (DBT/Phen) and (MDBT/MPhen) ratios show marine carbonate depositional setting. Type 2 oils show low (DBT/Phen) and (MDBT/MPhen) ratios and other biomarker features consistent with marine siliciclastic source rocks. On the other hand, type 3 oils have geochemical characteristics intermediate between those of types 1 and 2.

KEYWORDS:

• biomarkers
• crude oils
• dibenzothiophenes
• dipositional environment
• GC-MS
• maturity