利用三环萜烷对比泌阳凹陷生物降解油油源

以南襄盆地泌阳凹陷北部斜坡带生物降解油为例,在评价三环萜烷抗生物降解能力的基础上,研究了三环萜烷在生物降解油油源对比中的应用。对比分析表明,三环萜烷至少可以抵抗8级强度的原油生物降解,C23~C26/C19~C22-三环萜烷、C19~C26/C28~C29-三环萜烷及C19~C26-三环萜烷/C29-Ts等参数是有效的油源对比指标。三环萜烷指标、碳稳定同位素及三芳甾烷组成特征指示,泌阳凹陷北部斜坡带核三下亚段生物降解油来自深凹区核三下亚段烃源岩,核三上亚段生物降解油主要来自深凹区核三上亚段烃源岩。在珠江口盆地珠Ⅰ坳陷中,上述三环萜烷参数确定的油源关系与现有认识一致,进一步表明了这些参数的有效性。

Application of tricyclic terpanes in biodegraded oil-source correlation in Biyang Sag

Biodegraded oils from the northern slope of the Biyang Sag were analyzed to examine the application of tricyclic terpanes to biodegraded oil-source correlation. Tricyclic terpanes are resistant to biodegradation (biode-gradation rank 8) . New tricyclic terpane parameters, such as (C₂₃-C₂₆/C₁₉-C₂₂)-tricyclic terpanes, (C₁₉-C₂₆/C₂₈-C₂₉)-tricyclic terpanes and (C₁₉-C₂₆)-tricyclic terpanes/C₂₉-Ts are effective oil-source correlation parameters. Correlation results suggested that the biodegraded oils in the lower member of Eh₃ on the northern slope of the Biyang Sag came from the mudstones in the lower member of Eh₃ of the central sag, and the oils in the upper member of Eh₃ mainly came from the mudstones in the upper member of Eh₃ of the central sag. The correlation results of oils and source rocks in the ZhuⅠ Depression of the Pearl River Mouth Basin determined by the three tricyclic terpane parameters were consistant with previous results, further supporting the effectiveness of the parameters.