Chinese Science Bulletin

, Volume 45, Issue 14, pp 1341–1344 | Cite as

The migration fractionation: an important mechanism in the formation of condensate and waxy oil

  • Shuichang Zhang


Fault-initiated pressure release within reservoirs and the injection of external excessive dry gas may result in occurrence of oil and gas phases. Because of different partitioning coefficients of compounds in two phase flow, lower-molecular-weight components are easier to dissolve in gas phase, yielding condensates, while higher-molecular-weight components are retained in the oil phase, yielding waxy oil cumulations. The fractionation process causes extensive compositional variability in aliphatic/aromatic hydrocarbon ratios, molecular compound distributions and carbon isotope ratios that are traditionally considered to be related to the source organic matter or the thermal maturity.


migration fractionation condensate waxy oil Lunnan oil zone 


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Copyright information

© Science in China Press 2000

Authors and Affiliations

  • Shuichang Zhang
    • 1
  1. 1.Key Laboratory for Petroleum GeochemistryChina National Petroleum CorporationBeijingChina

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