萘菲系列化合物成熟度参数适用性探讨:基于热压生排烃模拟实验

Discussion on the applicability of maturity parameters of naphthalene and phenanthrene series compounds:insights from the thermocompression simulation experiment of hydrocarbon generation and expulsion

选取有机质类型为Ⅱ1型的烃源岩进行热压生排烃模拟实验,对排出油和滞留油中的萘菲系列化合物成熟度参数进行对比分析,同时结合实测镜质体反射率(R_(o))判断排出油和滞留油中成熟度参数的适用性。研究表明,随着模拟温度的升高,排出油和滞留油中的萘菲系列成熟度参数变化趋势基本一致,但不同参数的有效成熟度指示范围有所差别;对前人提出的基于萘菲系列成熟度参数计算等效镜质体反射率的方法进行验证,结果显示由二甲基萘参数DNR得出的等效镜质体反射率(R_(c))与实测镜质体反射率(R_(o))相关性较好,基于三甲基萘参数TNR-2、甲基菲指数MPI-1得到的R_(c)具有一定局限性;对比三甲基萘参数TMNr和四甲基萘参数TeMNr及甲基菲分布分数F_(1)和F_(2)对热演化程度的划分结果,发现应用三甲基萘参数和四甲基萘参数判断成熟度误差较大,甲基菲分布分数与R_(o)相关性较好,是良好的成熟度指标。

The hydrocarbon source rock with Type Ⅱ1organic matters was selected to conduct the thermocompression simulation experiment of hydrocarbon generation and expulsion, then maturity parameters of naphthalene and phenanthrene series compounds in the expelled oil and retained oil obtained from the experiment were analyzed comparatively. Meanwhile, the applicability of the maturity parameters of the expelled oil and retained oil has been judged in combination with the measured data of vitrinite reflectance(R_(o)). The results show that with the increase of simulation temperature, the variation trend of maturity parameters of naphthaline and phenanthrene series in expelled oil and retained oil is basically consistent, but the effective maturity indication ranges of different parameters are different in some extent. The method for calculating data of equivalent vitrinite reflectance based on maturity parameters of naphenanthrene series proposed by predecessors has been verified. It is found that the calculated data of equivalent vitrinite reflectance(R_(c)) based on the dimethylnaphthalene parameter(DNR) are in a good correlation with the measured data of vitrinite reflectance(R_(o)), but the calculated R_(c)values based on trimethylnaphthalene parameter(TNR-2) and methylphenanthrene index(MPI-1) are limitedly correlated with the measured R_(o)values. Comparing classification results of thermal evolution degrees based on the trimethylnaphthalene parameter(TMNr) tetramethylnaphthalene parameter(TeMNr), and methylphenanthrene distribution fractions of F1 and F2, it is found that there are relatively large errors in data of judged maturity by using trimethylnaphthalene parameter and tetramethylnaphthalene parameter, while there are relatively good correlations between the measured R_(o)data and the calculated R_(c)values based on methylphenanthrene distribution fractions. Thus, it is indicated that methylphenanthrene distribution fractions are good maturity indicators.