Characterization of organic matter and petroleum generation potental of the Middle Jurassic Kashafrud Formation, Eastern Koppeh-Dagh, NE Iran: Implications for improved petroleum system understanding

Articles in Press

Document Type : Research Paper

Authors

1 دانشگاه تهران، دکتری ژئوشیمی نفت

2 Department of Geosciences, University of Montanuniversität Leoben, Leoben, Austria

3 Exploration Directorate, National Iranian Oil Company (NIOC), Tehran, Iran

4 Petro Gostar Permayon Company, Tehran, Iran

Abstract

Geochemical characterization of organic matter (OM) from the Middle Jurassic Kashafrud Formation, as main possible source rock of the gas-fields in the Eastern Koppeh-Dagh from NE Iran, is main aim of this study. The total organic carbon (TOC) ranges from 0.10 to 1.37 wt% (on average: 0.46 wt%) and 0.04 to 1.5 wt% (on average: 0.56 wt%) for the surface sections and wells, respectively. Although mean residual TOC from the Kashafrud Formation is poor to fair but there are still good source rocks in the Formation that show higher content of carbonate with the higher TOC (up to 1.5 wt%). TOC and carbonate content show covariance. VRo ranges from 0,6 to 1,97% hence the kashafrud Formation is thermally early mature to over-mature. Kerogen is dominated by amorphoud organic matter (AOM) of phytoplanktonic origin with moderate to high amount of phytoclasts. Biomarker data confirms this result. The source rocks from the Kashafrud Formation, after maturing, generating, and expelling petroleum (gas and oil), can still be considered as a gas-prone source rock with Type III kerogen. Rock-Eval pyrolysis and organic petrography indicate presence of non-indigenous hydrocarbons (HCs) and therefore, confirm generation and expulsion of oil within the Kashafrud Formation. The mixed siliciclastic-carbonate facies, has played a more significant role in oil generation and expulsion. In the eastern Koppeh Dagh, there is still a chance of developing gas and even oil fields in potentual resrevoir rocks within the Kashafrud Formation and overlying formations.

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Article Title [Persian]

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Geopersia

Articles in Press, Accepted Manuscript
Available Online from 28 April 2025

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History

  • Receive Date: 26 January 2025
  • Revise Date: 06 April 2025
  • Accept Date: 28 April 2025

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