THE PROPERTIES OF MICROSPECTROFLUORIMETRY AND THERMAL MATURITY ASSESSMENT OF INDIVIDUAL OIL INCLUSIONS

摘要

The oil inclusions are called “minor reservoirs” which were trapped in the imperfections of diagenetic minerals or healed cracks,and carry abundant information of hydrocarbon migration and accumulation.It is,therefore,that the properties of microspectrofluorimetric analysis for individual oil inclusions become one of the powerful tools of complicated hydrocarbon migration and accumulation with multi-sources and multistages.On the basis of carding the mechanism of crude oils/oil inclusions emission fluorescence under UV excitation (365nm),the microspectrofluorimetric analysis for single oil inclusion integrated with structured light illumination microscopic imaging technique (SLIMIT) has been employed in this research to insight the influence factors of microspectrofluorimetric properties for the same oil inclusion assemblage (OIA).The results show that although both the chemical fractionation in the oil migration and accumulation and trapping fractionation during oil inclusion trapped are imposed on the properties of emission fluorescence of OIA,such as the peak wavelength altered within a small range (<20nm),the thermal maturities are the main controlling factor for the properties of OIA fluorescence.Consequently,it is essential to consider the influence factors,such as selective polar adsorption,oil cracking within inclusion and leakage of oil inclusion,during the thermal maturity assessment of individual oil inclusions.In practice,the best way is to use SLIMIT to recognize the altered oil inclusions first and then exclude them in analysis,the fluorescent properties of the rest oil inclusions are suitable for thermal maturity assessment,hydrocarbon charging events determination and tracing of hydrocarbon migration pathway.