Organic Matter Characteristics and Hydrocarbon Potential of Jurassic Sargelu Formation in X Well, Northern Iraq

Sargelu Formation from X Well, northern Iraq was studied to evaluate the hydrocarbon generation potential. To achieve this purpose, 15 rock samples were analyzed for Total Organic Carbon, Rock Eval pyrolysis and biomarkers analysis. The studied samples were classified as poor-excellent source rocks, in which they have Total Organic Carbon content in the range of 0.21% - 5.21 wt.%, with an average of 1.07 wt.%. There is gradually increasing with depth. Based on modified Van Krevelen diagram, most of the samples fall in the Kerogen type II and II/III except two samples which fall in the zone of type III. Unimodal normal alkane distributions, low Terrigenous to Aquatic Ratio values (ranging between 0.06-0.54), higher concentrations of C23 tricyclic terpanes relative to C19 tricyclic terpanes indicating minimal terrestrial input relative to aquatic sources. Pristane/Phytane ratios are in the range of 0.41-0.61 which indicate marine anoxic depositional environment. The C29/C30 ratios ranging between 0.65-1.04, indicated of anoxic marl or carbonate rocks. Tmaxvalues are in the range of 418-440oC, C29SS/SS+RR ratios ranged between 0.45–0.47 whereas C29ββ/ββ +αα ratios are between 0.51 and 0.53. The methyl phenanthrene index for studied sample is in the range of 0.53-0.60. All these results indicate immature-early mature organic matter.