Application Of SPME Technique In Oil Gas Geochemical Exploration

Solid phase microextraction (SPME) is a new pretreatment method for the samples analysis.With its extraction head, it can selectively absorb and enrich the trace target components from samples. At present, SPME technique has been widely used in many fields of chemical analysis, but the application in oil gas geochemical exploration has not been reported in China. For a long time, the demtermintion is foused on the light hydrocarbons (C1-C5), and there is not any effective method for the measurement of hydrocarbons above C5because of the low concentrations. SPME technique provides new ideas to solve this problem.On the basis of experiments, through a variety of type selection tests of extraction head, this thesis was established the type of the SPME and its extractve optimum conditions for the C5-C15hydrocarbons in the oil gas geochemical samples, then the testing conditions of GC, GC/MS been established to separate and identificate each component effectively. With the reference materials, the C5-C15hydrocarbons can be detected qualitatively and quantitatively by the retention time and MS library. Experiment shows that the recovery for most hydrocarbon components can be up to70%, and detection limit between10-9～10-10with the RSD%of about10%, which can satisfy the oil gas geochemical exploration.The SPME method of C5-C15hydrocarbons has been sucessfully applied in those samples of the Nanyang Depression, the Xifeng Oilfield in Ordos Basin and other areas, and the results show that the hydrocarbon anomalies detected by SPME method and the known oil fields areas have clear correlation. Meanwhile, it also achieves satisfactory results in the determinations in Sichuan Basin oil field water samples and oil samples.