Stable isotope geochemistry of coals, humic kerogens and related natural gases
Stable isotope geochemistry of coals, humic kerogens and related natural gases
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DOI：
10.1016/s0166-5162(96)00042-0
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发表时间：
1996-12
影响因子：
5.6
通讯作者：
M. Whiticar
中科院分区：
文献类型：
--
作者：
M. Whiticar
对于传统腐泥、I/II 型干酪根及其相关细菌和产热天然气产品，同位素系统学已得到明确定义。这些地球化学工具用于估计源类型、成熟度和沉积环境，并作为相关技术。在许多情况下，近地表样品和钻屑中的天然气特征可用于对更深的源岩或储层进行分类或预测。煤、III 型干酪根及其伴生碳氢化合物的相应解释方案正在迅速进展。人们对腐殖质来源的关注转移主要是由于常规石油和天然气资源的枯竭以及煤炭和煤层气的经济和社会需求。不同煤和腐殖质干酪根之间的碳、氢和氮稳定同位素变化可能很大。这些差异通常可以通过其本体 δ13Corg、δDorgand δ15Norg 值来识别。煤炭的同位素特征可以诊断多种因素，包括矿床年龄、类型、地理位置、成熟度和生成历史。然而，这些特征同位素变化基本上可以通过单独显质组（例如镜质体、外质体和惰质体）的 C、H 和 N 同位素比率来更好地定义。稳定同位素在显微组分和化合物水平上的新应用，与传统的全煤或散装技术相比，具有提高解释精度的巨大潜力。源自煤和腐殖干酪根的烃类气体（包括煤气）可以根据其分子比（即 C1(C2+ C3)）并通过比较其稳定同位素组成（尤其是 δ13CCH4 和 δDCH4）与 I/II 类来源区分开来。 δ13CC2H6 也很有价值，但乙烷通常含量很少（<1 vol.%）并且需要
Isotope systematics are well defined for conventional sapropelic, Type I/II kerogens and their associated bacterial and thermogenic natural-gas products. These geochemical tools are used to estimate source type, maturity and depositional environment, and as a correlation technique. In many cases the natural gas signatures in near-surface samples and drill cuttings can be used to classify or predict a deeper lying source rock or reservoir. Corresponding interpretative schemes for coals, Type III kerogens and their associated hydrocarbons are progressing quickly. The shift in attention to humic sources is driven primarily by depletion of conventional oil and gas resources and the economic and societal requirements of coal and coal-bed methane. Carbon, hydrogen and nitrogen stable isotope variations can be large between different coals and humic kerogens. These differences can often be recognized in their bulk δ13Corg, δDorgand δ15Norgvalues. Isotope signatures of coals can be diagnostic of several factors, including deposit age, type, geographic location, maturity and generation history. However, these characteristic isotopic variations are substantially better defined by the C-, H- and N-isotope ratios of the separate maceral groups, such as vitrinite, exinite and inertinite. This new application of stable isotopes, at the maceral and compound levels, have great potential to improve the interpretative precision over conventional whole coal or bulk techniques. Hydrocarbon gases, including coal gases, derived from coals and humic kerogens can be distinguished from Type I/II sources, based on their molecular rations, i.e., C1(C2+ C3) and by comparing their stable isotope compositions, especially δ13CCH4and δDCH4. The δ13CC2H6can also be valuable, but ethane is generally present in small amount (<1 vol. %) and requires