摘要
烃源岩的矿物组成可能会对可溶有机质的赋存状态产生显著的影响,进而影响烃源岩的生排烃行为以及页岩油资源的勘探开发。本文对东营凹陷沙河街组两个低熟湖相泥质烃源岩进行了分级抽提实验,获取了烃源岩中不同赋存状态的可溶有机质,依次为:呈游离态的和以物理吸附在干酪根或矿物表面的可溶有机质(氯仿沥青"A")、与碳酸盐矿物紧密结合或被其包裹的可溶有机质(氯仿沥青"C")、与硅酸盐矿物或干酪根紧密结合的可溶有机质(氯仿沥青"E")。通过气相色谱-质谱联用仪(GC-MS)和傅里叶变换-离子回旋共振质谱(FT-ICR MS)等分析手段,研究了各种赋存状态可溶有机质族组成、饱和烃以及极性化合物的组成及分布特征。结果显示:两种烃源岩的氯仿沥青"A"都约占总可溶有机质的90%左右,且氯仿沥青"A"和氯仿沥青"E"含量可能与总有机碳含量有关。不同赋存状态可溶有机质在族组成上存在明显的差异:自氯仿沥青"A"至"C"再至"E",饱和烃和芳烃含量依次下降,而胶质和沥青质的含量依次上升,这可能与不同矿物基质对可溶有机质的选择性吸附或富集作用差异有关。FT-ICR MS分析结果显示:中性含氮化合物主要富集在氯仿沥青"A"中,而氯仿沥青"C"和"E"中的极性化合物主要为各种强极性的含氧化合物。本工作对揭示低熟湖相泥质烃源岩中可溶有机质的富集机理具有重要意义。
The composition of minerals may have some remarkable effects on the physical state of soluble organic matter in hydrocarbon source rocks,and thus influences hydrocarbon generation and expulsion of the source rocks,as well as exploration and production of shale oils.In this study,a sequential extraction experiment of two low-maturity argillaceous source rocks from the Shahejie Formation in the Dongying Depression was performed to obtain soluble organic matter with different states in the source rocks.This soluble organic matter was assigned to organic matter that is free and physically adsorbed onto the surface of minerals or kerogen(namely bitumen“A”),organic matter that is firmly combined with or occluded within carbonates(namely bitumen“C”),and organic matter that is closely combined with silicates or kerogen(namely bitumen“E”).A combination of gas chromatographymass spectrometry(GC-MS)and Fourier transform ion cyclotron resonance mass spectrometry(FT-ICR MS)was employed in the analysis of oil fractions,saturates,and polar compounds in the soluble organic matter.The results reveal that bitumen“A”accounts for approximately 90%of the total soluble organic matter in the two source rocks,and that both bitumen“A”and“E”may be relevant to total organic carbon.Moreover,there were significant differences in the compositions of soluble organic matter within different physical states.In the sequence of bitumens“A”,“C”,and“E”,both saturated and aromatic fractions gradually decrease,while resin and asphaltene fractions progressively increase.This may be attributed to selective adsorption or differential enrichment of the mineral matrix to soluble organic matter.FT-ICR MS analysis of the soluble organic matter also shows that neutral nitrogen-containing compounds are prevalent in bitumen“A”but absent in bitumens“C”and“E”,and that polar compounds in both bitumens“C”and“E”are dominated by oxygen-containing compounds with stronger polarity.This study is of great significance in the exploration of the enrichment mechanism of soluble organic matter in low-maturity argillaceous source rocks of lacustrine facies.
作者
潘银华
黎茂稳
孙永革
李志明
蒋启贵
廖玉宏
PAN Yin-hua;LI Mao-wen;SUN Yong-ge;LI Zhi-ming;JIANG Qi-gui;LIAO Yu-hong(Department of Earth Science,Zhejiang University,Hangzhou 310027,China;SINOPEC Key Laboratory of Petroleum Accumulation Mechanisms,Wuxi Institute of Petroleum Geology,SINOPEC Petroleum Exploration and Production Research Institute,Wuxi 214126,China;State Key Laboratory of Organic Geochemistry,Guangzhou Institute of Geochemistry,Chinese Academy of Sciences,Guangzhou 510640,China)
出处
《地球化学》
CAS
CSCD
北大核心
2018年第4期335-344,共10页
Geochimica
基金
国家重点基础研究发展计划(2014CB239101)
有机地球化学国家重点实验室开放基金(SKLOG-201601)
中国科学院战略性先导科技专项(B类)子课题(XDB10010301)。
