Quantitative Evaluation of Petroleum Maturity of Different Periods of Charging of Ordovician Reservoirs in Tahe Area Using Fluorescence Spectrum Parameters of Oil
The crude oil in the reservoirs in the Tahe area is mainly derived from the Cambrian Yuertusi source rocks. The discovered oil reservoirs are the result of mixing of crude oils of different stages and different maturities in the reservoirs. Based on the analysis of reservoir oil maturity and fluorescence spectra,this paper uses fluorescence spectrum parameters to establish a quantitative evaluation template for crude oil maturity,and assesses the maturity of crude oil at different episodes in the Tahe area by obtaining oil inclusion fluorescence spectrum parameters. The analysis results of the maturity parameters of crude oil show that the methylphenanthrene parameters and dibenzothiophene parameters in aromatic hydrocarbons are effective indicators for quantitatively evaluating the maturity of crude oil in Tahe area. Using aromatic hydrocarbon maturity parameters to calculate,the crude oil maturity (Ro) in Tahe area ranges from 0.6％ to 1.4％,which has a good correlation with the crude oil fluorescence spectrum parameters,and a quantitative evaluation template for crude oil maturity is established based on the relationship between the two. The fluid inclusion analysis results show that there are four periods of petroleum charging in the Ordovician carbonate reservoirs in the Tahe area,corresponding to oil inclusions with orange,bright yellow,light yellow,and blue fluorescence. The fluorescence spectrum parameters of oil inclusions in different periods are also different. Based on the fluorescence spectrum parameters of oil inclusions in different periods and the established fluorescence spectrum parameters-maturity evaluation template of crude oil,it is determined that the maturity (Ro) of oil in orange fluorescent oil inclusions is less than 0.6％,that of oil in bright yellow fluorescent oil inclusions is between 0.6％ and 0.8％,that of oil in light yellow fluorescent oil inclusions is between 0.8％ and 1.0％,and that of oil in blue fluorescent oil inclusions is between 1.0％ and 1.2％.The determined maturity of petroleum in different periods has an important reference for the study of petroleum accumulation process in Tahe area.
维普
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