受生烃母质控制的干酪根及其热解产物稳定碳同位素分布模式
Stable carbon isotope distribution patterns of kerogen andits derived hydrocarbons constrained by primary biomass

刘虎 ¹ 廖泽文 ² ^* 戚明辉 ³ 张海祖 ⁴ 杜军艳 ⁵ 杨珊 ²

文摘	塔里木盆地来源于寒武系-下奥陶统烃源岩的原油与其母质干酪根的稳定碳同位素存在倒转现象,为验证这种同位素倒转并探讨其可能原因,选取华北下花园地区的下马岭组灰质页岩和泥质页岩,以及新疆三塘湖盆地的芦草沟组泥质页岩样品开展热模拟实验。结果在下马岭组灰质页岩干酪根热解残渣和其热解油之间发现了这种碳同位素的倒转分布。与未发现碳同位素倒转现象的下花园地区和三塘湖盆地的泥质页岩样品相比,下马岭组灰质页岩干酪根热解油的稳定碳同位素变化幅度相对较大,而残渣的碳同位素变化幅度相对较小。结合有机岩石学及生物标志化合物综合分析发现,下马岭组灰质页岩中间隔分布的"下花园藻残片"生烃能力相对较差,且几乎没有检测到甾、萜类生物标志化合物;而在另外两组泥岩的热解产物中并没有发现这种现象,显示了下马岭组灰质页岩具有特殊的母质类型或沉积环境。由此可见,下马岭组灰质页岩干酪根及其热解产物之间的稳定碳同位素倒转分布很可能与早期生命体特殊的生物化学组成,或者早期的类异戊二烯烃类在沉积过程中更难以被保存下来等因素有关。
其他语种文摘	There exists a stable carbon isotope reversal between crude oils and kerogens from the Cambrian-Lower Ordovician source rocks of the Tarim Basin, NW China. To verify the inverse carbon isotopic pattern and probe the possible mechanism, three shale samples with low thermal maturity were used for thermal simulation experiments, two of which were taken from the Neoproterozoic Xiamaling Formation in Xiahuayuan region, North China (one from argillaceous shale and the other from calcareous shale) and the third one was from the Permian Lucaogou Formation in Santanghu Basin, Northwest China (argillaceous shale). A reversed carbon isotope distribution pattern between kerogen residue and its pyrolysates was observed for the Xiamaling calcareous shale, which was not found for the Xiamaling argillaceous shale or Lucaogou argillaceous shale. A stronger carbon isotope fractionation was found for the pyrolysates from Xiamaling calcareous shale kerogen than those from argillaceous shale kerogens, and then accordingly a weaker carbon isotope fractionation was determined for the pyrolyzed residues from Xiamaling calcareous shale kerogen. Combined with organic petrology and thermal simulation experiments, the "Xiahuayuan algal relic" from Xiamaling calcareous shale was supposed to have a lower hydrocarbon generation capacity than the mineral bituminous matrix from Xiamaling argillaceous shale and the laminated algae from Lucaogou argillaceous shale. Combined with biomarker distribution features, it was suggested that the reversed carbon isotope pattern, between kerogen residue and its pyrolysates, may be ascribed to the contribution of some special biomass (primarily constituted by n-alkanes) of early life, or the isoprenoid compounds were less preserved in the process of biomass sedimentation.
来源	石油实验地质 ,2016,38(5):652-658,664 【核心库】
DOI	10.11781/sysydz201605652
关键词	同位素倒转 ; 热模拟实验 ; 干酪根 ; 下马岭组 ; 下花园地区 ; 华北
地址	1. 中国科学院广州地球化学研究所, 有机地球化学国家重点实验室;;页岩气评价与开采四川省重点实验室, 广州, 510640 2. 中国科学院广州地球化学研究所, 有机地球化学国家重点实验室, 广州, 510640 3. 页岩气评价与开采四川省重点实验室, 页岩气评价与开采四川省重点实验室, 成都, 610091 4. 中国石油塔里木油田分公司勘探开发研究院, 新疆, 库尔勒, 841000 5. 广西海洋研究院, 南宁, 530022
语种	中文
文献类型	研究性论文
ISSN	1001-6112
学科	石油、天然气工业
基金	国家自然科学基金项目
文献收藏号	CSCD:5823105