Biological Marker Fingerprints of Crude Oils from Three Oilfields in the Central Niger Delta: Implication to Source Input, Conditions of Deposition, and Thermal Maturation

Crude oil samples recovered from three oilfields distributed within the central Niger Delta were used to investigate biological marker fingerprints, sources of organic matter, conditions deposition, and thermal maturation. This was achieved by application gas chromatography-mass spectrometric (GC-MS) analyses on saturated components crude oils. The ratios show low sterane/hopane (steranes/hopane ˂ 1) in scope 0.29 0.61 indicating that oils initiated rocks containing high terrigenous biota (mainly land plants). n-alkanes distribution pristane/phytane (0.63 2.08) suggested source deposition under oxic suboxic environmental conditions. percentage composition C27, C28, C29 steranes oleanane index (18α (H)-oleanane/ C30 17α (H)-hopane) also indicated major contributions with minor marine input. studied have C32:22S/ (22S+22R) 0.55 0.64, these values maturation level. agrees (0.64 0.95), CPI (0.92 1.06), C29: 20S/ (20S + 20R) sterane (0.29 0. 61), Ts/(Ts+Tm) ratio (0.45 0.83) moretane/C30 hopane proportion (0.16 0.24). Keywords: Biological marker; Depositional conditions; Delta; Organic matter; Thermal