不同藻类热模拟实验的生烃特征对比

针对多细胞宏观底栖藻紫菜在不同演化阶段的生烃特征开展了封闭体系加水热模拟实验,并与浮游藻和单细胞藻类生烃特点进行了对比。实验结果表明:随着温度的升高,多细胞藻类的生烃率呈双峰分布,低熟阶段是釜壁轻质油的主要产出阶段;气携凝析油在成熟阶段达到生成高峰,气态烃与液态烃产率相当;高成熟阶段因为有机质裂解和液态产物的裂解,气态烃成为排出烃的主要组成部分。不同藻类的生烃高峰及产物的组分在不同成熟阶段各有特点,浮游藻类的脱氧反应主要发生在成熟阶段,而单细胞和多细胞藻类的脱氧反应主要发生在低成熟阶段。液态产物方面,浮游藻类和多细胞藻类在低成熟和成熟阶段以非烃质产物为主,而单细胞藻类以沥青质为主。高成熟阶段,单细胞藻类的芳烃比例明显增高,而饱和烃产率以多细胞底栖藻类为最高。不同藻类产生的液态产物在族组分上的差异,对资源评价的精度具有一定影响。

COMPARISON OF CHARACTERISTICS OF HYDROCARBON GENERATION FOR DIFFERENT ALGA

Porphyra yezoensis hydrous pyrolysis in closed system at different maturity stages were carried out,and their hydrogenation generation characteristics were compared with those of plankton and single cell alga.Double-peaked hydrocarbon production rate was appeared with the temperature ascending in multi-cell benthic macro alga.Light oil was the main product in lower maturation period;gas-carried condensate oil reached its peak and the product rate of gaseous and liquid hydrocarbon was equivalent during maturation period.Gaseous hydrocarbon was dominated because of both the organic matter and liquid hydrocarbon pyrolysis during the high-matured period.The different kinds of alga have different models for hydrocarbon ge-neration and expulsion at different thermal evolution stages.For deoxidation reaction,the plankton alga occurred during the maturity stage while the single and multi-cell alga occurred during low-maturity stage.For the liquid products,the non-hydrocarbon was the main product for plankton and multi-cell alga in both low-maturity and maturity stages,while the asphaltene was the main product for single cell alga in the same stage.In the post-maturity stage,the aromatic hydrocarbon content arose in single-cell alga while the multi-cell alga had the most of saturated hydrocarbon product.The difference of family group for different kinds of alga can affect the resource assessment in certain degree.