Palynofacies Analysis and Hydrocarbon Generation Potential of the Tithonian-Beriassian Chia Gara Formation from Selected Wells in Ajil, Hamrin, and Tikrit Oilfields, Northern Iraq

The recovered sedimentary organic matter from the Tithonian-Berriasian Chia Gara Formation was studied from three selected wells of Ajil-12 (Aj-12), Hamrin-1 (Hr-1), and Tikrit-3 (Tk-3) in Northern Iraq. Amorphous organic matters appeared to be the dominant components of the organic matters within the formation with more than 93%, whereas phytoclasts and palynomorphs comprised only few percentages. As no intensive variations observed in the percentages of the determined organic matters along the studied Chia Gara Formation except a slight increase in phytoclasts and palynomorphs in its uppermost part, therefore the formation considered to be representing only one mainpalynofacies type that subdivided into two secondary palynofacies. Using Tyson's APP ternary, the formation appeared to be deposited in a distal suboxic-anoxic basin. As source rock, the formation in the studied locations contains moderate to very good quantity of organic matters which compose mainly of type II and Type III kerogen (separately or mixed). The whole formation has the ability to generate oil or gas except the upper part of the formation in the location of the well Aj-12 in which less than the lower limit of the required S2 values for considering as source rock is recorded.