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oa δD Distribution of Light/Condensate Oils and Their Methyl Aromatics in Tazhong Area of Tarim Basin, China and Their Geochemical Significance
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, IMOG 2025, Sep 2025, Volume 2025, p.1 - 2
Abstract
Aromatization widely occurs during the evolution process of light oil/condensate (LOC). The LOCs from the Tazhong area of the Tarim Basin, northwestern China, were analyzed to investigate the light methyl aromatic components and their hydrogen isotope distribution characteristics, and further their geochemical significance.
The LOC from Well ZG432 is enriched in 13C but depleted in 2H, which significantly differs from other LOC in the region but closely resembles that of the TZ62(S) crude oil. The dD values of methylcyclohexane, toluene, and methylnaphthalene in LOCs from the Tazhong I structural belt are generally higher than those from the Tazhong 10 structural belt. The thermal maturity of LOCs from the Tazhong I fault-slope zone is slightly higher than that of oils from the Tazhong 10 structural belt, likely due to more intense gas washing in the former.
The Furongian strata deposited in the period of the Cambrian SPICE event in the Tarim Basin is characterized by enriching 13C and depleting 2H in their kerogen, similar to the 13C-enriched crude oils. In addition to contributions from Lower Cambrian and Middle–Upper Ordovician source rocks, these crude oils may have received contributions from upper Cambrian Furongian source rocks deposited in locally shielded environments.
