ISOLATION, CHARACTERIZATION AND GEOCHEMICAL SIGNIFICANCE OF PORPHYRINS IN CRUDE OILS FROM GULF OF SUEZ

Five crude oil samples, covering a wide range of maturation, were coll ected from the major producing fields in the Gulf of Suez area. The oi l fields were West Bakr, Um-Elyse, Morgan, Ras Gharib, and Shoab Ali. Demetallated petroporphyrins and metalloporphyrins were isolated from residual fraction > 200 degrees C of the crude oils using acetic acid/ HCl-HBr system and chromatographic adsorption method, respectively. Th e isolated porphyrins were characterized and estimated by W-visible sp ectroscopy. The adsorption method not only isolated metalloporphyrins but also separated vanadyl porphyrins and nickel porphyrins individual ly. The results indicated the presence of deoxophylloerythreoetioprphy rins [DPEP] and etioporphyrins in the studied crude oil samples. The a mount of vanadyl porphyrins exhibited a good relationship with the con tents of both sulfur and asphaltene in the crude oils whereas no evide nt relation was observed with the concentration of nickel porphyrins. The effect of reservoir depth and maturation level of the crude oils o n the concentration of metalloporphyrins were geochemically assessed.