Integrated organic geochemistry with palynofacies analysis of the Chia Gara Formation in the Kirkuk and Hamrin oilfields, North Iraq

The idea of the present work was to combine Rock-Eval pyrolysis and palynofacies analysis in an integrated approach to study 51 source rock cores and cuttings samples collected from the middle TithonianBerriasian Chia Gara Formation, in well K-109, Kirkuk Oilfield and well Hr-1 drilled in the Hamrin Oilfield, north of Iraq to evaluate quantitatively and qualitatively the nature of sedimentary organic matter, generation potential and assess thermal maturity of the studied formation in both wells. Rock-Eval pyrolysis and palynofacies data indicate that the Chia Gara Formation in well K-109, Kirkuk Oilfield has kerogen type III/II and II/I and the amorphous organic matter AOM is dense and amber brown to very dark brown in color assigned to type C and D which reflects mature to overmature stage (gas-oil prone). On the other hand, the source rock samples of the Chia Gara Formation encountered in well Hr-1, Hamrin Oilfield has kerogen type II/III and II/I and the AOM is dense rounded, yellow to yellowish brown typeD, mature and is oil-gas prone. The regional tectonic movements and thermal history may cause the diversity in kerogen type and the subtle color variation in the AOM from the Chia Gara Formation in the Kirkuk Field in the north to Hamrin Field in the south.