单个油包裹体显微荧光特性与热成熟度评价

Microspectrofluorimetric characterization and thermal maturity assessment of individual oil inclusion

油包裹体是捕获于成岩矿物晶体缺陷或愈合裂纹中的"微观油藏",携带着丰富的油气成藏过程信息。单个油包裹体显微荧光特性分析成为叠合盆地多源多期复杂成藏过程研究强有力的工具之一。运用单个油包裹体显微荧光分析和结构光纳米显微成像技术,讨论了同一期次油包裹体显微荧光特性的影响因素,认为原油在运聚过程中的化学分馏和捕获过程中的捕获分馏会造成同一期次油包裹体荧光特性在一定范围内波动,但热成熟度仍然是影响单个油包裹体显微荧光特性的主要因素。因此,需要考虑选择性极性吸附、包裹体油裂解和泄漏对单个油包裹体显微荧光热成熟度的影响。最佳的办法是运用结构光成像技术识别出受影响的油包裹体并加以剔除,这样单个油包裹体显微荧光特性参数还是可以应用于热成熟度评价的。

The oil inclusions are micro-reservoirs trapped in crystal defects or healed cracks of diagenetic minerals,carrying considerable information of hydrocarbon migration and accumulation.Microspectrofluorimetric analysis of individual oil inclusions thus becomes one of the powerful tools for researching complex processes of hydrocarbon migration and accumulation with multi sources and multi stages in superimposed basins.In this study,microspectrofluorimetry and structured illumination microscopy of individual oil inclusions are applied to investigate factors influencing microspectrofluorimetric characteristics of oil inclusion assemblages （OIAs） formed in the same period.Both chemical fractionation during oil migration-accumulation and trapping fractionation during inclusion trapping cause certain fluctuations in the fluorescence emission of OIAs.However,thermal maturity remains the main controlling factor of the microspectrofluorimetric characteristics of OIAs.Therefore,it is essential for thermal maturity assessments of individual oil inclusions to consider the influences of selective polar adsorption,oil cracking within inclusion,and leakage of oil inclusion on the microspectrofluorimetric characteristics of OIAs.The best approach is using structured illumination microscopy analysis to identify the altered oil inclusions and then exclude them from the following analysis.In this way,the microspectrofluorimetric characteristics of the remaining individual oil inclusions are still suitable for thermal maturity assessment.