Geochemical application of alkane and triterpane biomarkers to a description of crude oils from Egypt

ABSTRACT

Two Egyptian crude oil samples from the Western Desert [Alamein] and Gulf of Suez [Badran] were characterized by geochemical application of alkane and triterpane biological markers. Saturated hydrocarbon fractions obtained by medium pressure liquid chromatographic [MPLC] separation of the oils were analyzed by GC and GC/MS. The results indicated the presence of several homologous series. Normal alkanes [C8-C40] were the major constituent series while, acyclic isoprenoids [C13-C20, except C17], monomethyl-branched alkanes [mainly 2- and 3-methylalkanes], cyclic alkanes and hopanes were the minor constituent series. The results show that the oils were derived from a similar source materials i.e. terrigenous organic matter. The high pristine/phytane ratios suggest the likely prevalence of highly oxic depositional environments. Maturity related parameters based on CPI, EOP, C30 beta alpha/alpha beta and C31 22S/[22S + 22R] were almost identical