生物标志化合物热成熟度参数演化规律及意义——以Ⅲ型烃源岩HTHP生排烃热模拟液态烃产物为例

Evolution patterns and their significances of biomarker maturity parameters—a case study on liquid hydrocarbons from type Ⅲ source rock under HTHP hydrous pyrolysis

孙丽娜 张中宁 吴远东 苏龙 夏燕青 王自翔 郑有伟

Sun Lina Zhang Zhongning Wu Yuandong Su Long Xia Yanqing Wang Zixiang Zheng Youwei

为了探究烃源岩不同热演化阶段生物标志化合物成熟度参数的演化规律及其专属指示意义。通过对辽河盆地桃10井Ⅲ型烃源岩进行HTHP生排烃热模拟实验，获取的液态烃产物饱和烃组分进行GC/MS分析，以模拟温度为成熟度标尺，检测出正构烷烃、类异戊二烯类烷烃、三环二萜烷、藿烷及甾烷系列中对热成熟度演化具有一定指示意义的生物标志化合物，并计算出参数指标。依据不同生物标志化合物对热作用的敏感程度不同，利用不同热敏感性的生标化合物比值指示热演化阶段。结果发现，随着模拟温度的升高，藿烷会受热作用影响形成三环萜烷，Tm会转化为Ts，20型生物型异构体会向20型地质异构体转化，所以∑三环萜烷／∑藿烷、Ts/Tm和C-藿烷22／（22+22）参数对有机质热演化阶段可以起到较好的指示作用。而受热作用的差异性影响，参数C-四环萜烷／∑藿烷、C-莫烷／C-藿烷和C-甾烷／（+）则在成熟至过成熟阶段具有更强的指示意义。由此可见，样品不同热演化阶段均有其最佳适用的生标参数组合，这为正确利用成熟度参数判识该地区烃源岩成熟度演化阶段提供了一定的理论依据。

High temperature and high pressure hydrous pyrolysis experiments were conducted on type Ⅲ source rocks from Well Tao 10 in Liaohe Basin under various conditions to investigate the role of biomarker maturity parameters at different thermal evolution stages.The expelled oils collected from these experiments were separated into saturated hydrocarbons, aromatic hydrocarbons, non-hydrocarbons and asphaltene, and the saturated fractions were analyzed by GC/MS.Taking the simulation temperature as the scales of maturity, the biomarkers that are indicative of thermal maturity evolution were detected from n-alkane, isoprenoid alkane, tricyclic terpane, tetracyclic terpane, hopane and sterane, and their parameter index were also calculated.Based on the different sensitivities of different biomarkers to thermal action, the ratio of different biomarkers may reflect different thermal stages.With the simulation temperature increasing, the hopanes may be turned into tricyclic terpanes, Tm may be turned into Ts, and the configurations of isomers will be transformed from 22 to 22, thus the ∑tricyclic terpane/∑hopane, Ts/Tm and C-hopanes 22/(22+22) may be good indicators of thermal stages.But in the stage of maturity to over-maturity, the C-tetracyclic terpane/∑hopanes, C-moretane / C-hopane and C-sterane /(+) are more suitable indicators.Therefore, samples at different thermal evolution stages have their own optimal biomarker assemblages providing a theoretical basis for determining thermal evolution stage of source rocks by using maturity parameters in the study area.

10.11743/ogg20150406