Kurra Chine Formation: Evaluation of Source Rock, Based on Rock-Eval Pyrolysis Analysis Integrated by Selected Wells and Outcrop Samples in Iraq's Kurdistan Region

Abstract

The current research deal with evaluating the Late Triassic Kurra Chine Formation using the Rock-Eval Pyrolysis technique in selected wells in Sarta-2 and Tawke-17 Oil fields, and the Sirwan Valley outcrop, in Northern Iraq. A total of twenty-six samples were selected for this study; nineteen cuttings samples from the wells and seven outcrop samples from Sirwan Valley. The total organic carbon wt.% of the formation in Sarta oilfield samples ranges 0.43–2.51, and in Tawke samples ranges between 0.13–1.52, and for Sirwan Valley ranges between 0.02–0.32. Based on the total organic carbon content the Kurra Chine Formation can be considered as poor to very good source rock in the Sarta Oil field and poor to good in Tawke, and poor to fair source rock in Sirwan samples. Generation Potential shows some potential to generate good source potential, moderate source potential, and poor generation potential in the Sarta well, Tawke well, and Sirwan Valley as Generation Potential ranges between 1.47–8.55, 0.48–4.46 and 0.02-0.11, respectively. The values of S1 range between 0.57–4.13, 0.15–1.02 and 0.01–0.03 mg HC/g rock for Sarta, Tawke, and Sirwan Valley respectively. Based on the S1 values the Kurra Chine Formation is considered fair to excellent, fair to good and poor source rock in the Sarta, Tawke, and Sirwan respectively. The analyzed samples show an immature level with Tmax ranges between 292-405 and immature to early mature with Tmax between 425-439 and immature to postmature with Tmax values between 339–597 for Sarta, Tawke, and Sirwan respectively. Tmax-HI plot shows Kerogen types (II-III, III-IV), (II to III), and (III-IV) for Sarta, Tawke, and Sirwan Valley respectively.