Biological markers in crude oils from Egypt

ABSTRACT

The main aim of this study was to investigate source -and maturity- dependent trends of a number of biomarker parameters in two Egyptian crude oil samples from Alamein and Badran oil-fields. The aliphatic and aromatic hydrocarbon fractions were examined by gas chromatography and combined gas chromatography-mass spectrometry. In all fractions, there is a high relative abundance of components of higher-plant origin. Molecular maturity measurements indicated that both oils are at an advanced level of thermal maturity and many ratios, such as CPI, C30 alpha beta/alpha beta + beta alpha hopanes, C31 22S/22S + 22R hopanes, C29 alpha alpha alpha-20S/20S + 20 R steranes, C29 alpha beta beta/ alpha beta beta + alpha alpha alpha steranes and methylphenanthrene index [MPI 1] have reached their thermal equilibrium values. Changes in the two trisnorhopane [Ts/Tm] ratio. However, showed a more advanced level of thermal maturity for Alamein oil and correlated well with trends of organic sulfur compound ratios and aromatic steroid cracking ratios