Occurrence and distribution of n-alkanes and n-fatty acids in Saudi Arabian crude oils

Ten crude oil samples, covering wide range of maturity (API gravity = 18.5- 36.1), were assembled from Safaniya, Abqiq, Ain Dar, Wafra. Marjan and Zulu foil fields in the area of Arabian Gulf. n-Alkanes of were separated from t he petroleum distillate ((150 degrees C-450 degrees C) of the crude oils by urea adduction. n-Fatty acids were separated from the fraction of n-alkane s by treatment with aqueous solution of KOH. Distribution of n-alkanes and n-fatty acids has been investigated by means of gas chromatography. The stu died crude oils showed symmetrical distribution curves of n-paraffins and f atty acids of low molecular weight were abundant as compared with n-paraffi ns. The n-paraffins distribution curve of Wafra/Iucene biodegraded immature crude oil showed three maxima at C-17, C-19, and C-31 whereas the maxima o f n-fatty acids are located at C-14, C-22 and C-24 The results were interpr eted in terms of origin, maturation and depositional environments of the cr ude oils.