不同干酪根类型烃源岩热解石油与石油包裹体显微荧光光谱特征比较研究

The relationship of fluorescence color of oil bearing fluid inclusion(OFI) and its maturity has be widely used in the oil and gas migration and accumulation. However, the fluorescence color of OFI is not only controled by the thermal maturity of its source rock, but also related to organic matter types of the source rock, primary migration compositional fractionation, secondary migration compositional fractionation and trapping fractionation of OFI an so on. Thereby, the premise for analysing the relationship between the fluorescence color of OFI and its maturity is to find out the effects of those factors above.Based on the problem that various factors dominate the alteration the fluorescense color,Resource rock with different types of kerogen and petroleum inclusions are taken as research objects, pyrolysis experiment of source rock in finite space, geological case studies and synthetic OFI experiment are conducted for quantitative evaluation of the effects of kerogen types and its thermal maturity, petroleum primary migration compositional fractionation, secondary migration compositional fractionation and trapping fractionation of OFI on the fluorescence spectrum of OFI, and the modification of spectrum parameter and fluorescense color will be calibrated according to the experiments and geological cases results from initial petroleum generation in source rock to trapped as fluid inclusion. The project is expected to build the quantitative relationship between thermal maturity paremater of kerogen (Ro) and fluorescence spectrum parameter (QF535) of OFI. The project resutls is extraordinarily useful and constructive for directly evaluating the thermal maturity of source rock which is responsible for inclued oil in OFI and constraining the hydrocarbon generation history and the timing of petroleum migration and accumulation.

石油包裹体荧光颜色与其成熟度关系已经被广泛应用于油气成藏研究。然而，其荧光颜色不仅受控于其源岩的热成熟度还与源岩有机质类型、初次运移组分分馏、二次运移组分分馏以及包裹体捕获分馏等诸多地质过程有关。因此，弄清以上因素对石油包裹体荧光颜色的影响是分析其荧光颜色与其成熟度关系的前提。针对石油包裹体荧光颜色变化受多种因素控制问题，以不同类型干酪根源岩和石油包裹体为研究对象，采用烃源岩有限空间生油模拟实验、地质实例以及人工合成包裹体实验等方法对比研究了干酪根类型和成熟度、石油初次运移组分分馏、二次运移组分分馏以及包裹体捕获分馏等过程对其荧光光谱的影响，最终校正了不同类型干酪根源岩热解石油荧光颜色及光谱参数的变化。项目预期建立不同类型干酪根源岩成熟度（Ro）与石油包裹体荧光光谱参数（QF535）之间的定量关系，项目成果对于直接评价包裹体油对应源岩的成熟度以及约束烃源岩生烃史及油气成藏时期具有重要意义。

油包裹体荧光颜色很早就被用来指示原油成熟度，原油成熟度越高其荧光颜色向蓝色偏移，反之原油荧光颜色向黄色偏移（“蓝移”和“红移”）。由于油包裹体是油气充注过程中被捕获的微观古流体，获取包裹体内原油的成熟度对油气成藏研究意义重大。因此，基于原油荧光颜色与成熟度的关系，利用油包裹体荧光颜色来预测包裹体油的成熟度已经成为油气成藏研究中的常用方法。然而，近些年来，一些研究认为原油荧光颜色与其成熟度关系并不可靠，除了烃源岩成熟度外，烃源岩有机质类型、原油运移过程中水洗、生物降解等因素均会改变原油荧光颜色。.本项目以烃源岩热解生油实验为基础，主要研究东营凹陷不同干酪根类型烃源岩生成原油和实际地质样品中油包裹体的荧光光谱特征，弄清原油荧光颜色变化的主要控制因素以及通过荧光光谱参数定量计算油包裹体热成熟度，从而为油气成藏过程重构提供更准确的约束。.项目研究结果表明：（1）相同成熟度不同干酪根类型对原油荧光光谱特征控制，II型干酪根生成油荧光颜色相对I型偏“蓝移”；（2）原油荧光光谱参数（λmax，Q和QF-535）随烃源岩热成熟度增加先增大后减小，只有Ro达到0.66-0.77%以后，荧光光谱参数（λmax，Q和QF-535）开始随烃源岩成熟度增加逐渐减小，表明只有在Ro大于0.66-0.77%以后热成熟度对原油组分的影响才显著，而生油早期烃源岩排出油荧光特征主要受排烃过程控制；（3）烃源岩排油效率对排出油荧光光谱参数变化影响较大，特别是在生油早期（Ro<0.66-0.77%），排油效率越高，排出油质越重，反之油质越轻。