The scope of this study was to develop robust lithofacies proxies which are less affected by other geochemical processes such as maturity and biodegradation. Here, crude oils derived from carbonate and siliciclastic source rocks from different petroleum settings were investigated using Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS), thereby providing information on the role of depositional environment in controlling the chemical composition of hydrocarbons. The carbonate oils belong to the Western Canada Sedimentary Basin (WCSB) and the siliciclastic oils were mainly collected from the Austrian parts of the Molasse Basin and the Vienna Basin, Austria. The variations in chemical composition, aromaticity as well as alkylation degree of the main compound classes in both oil types are discussed in detail using data from FTICR-MS in two different ionization modes: electrospray ionization in negative ion mode (ESI–N) and atmospheric pressure photoionization in positive ion mode (APPI–P). The results obtained from both ionization modes indicate that the chemical compound distributions of acidic constituents such as oxygen-only components (the O₁ to O₄ classes) and the N₁S₁ class, as well as sulfur and hydrocarbon species in oils from carbonates are clearly different from those generated by siliciclastic rocks. Most likely, the observed differences are attributed to depositional environments of the respective source rocks as the impacts of other processes such as thermal maturity and biodegradation, were mitigated by selection of non-biodegraded oils that display comparable maturation levels. The calculated vitrinite reflectance (%Rc) in most of the selected oils range between 0.5 and 0.8. The observed differences in chemical composition of oils from carbonates and siliciclastics lead to suggested novel source-sensitive proxies based on the DBE distribution of the S₁ and HC species (from APPI–P) and the O₁ and N₁S₁ classes (from ESI–N). The former proxy is the ratio of the S₁ class DBE 9 group (radical ions; likely sum of alkylated dibenzothiophenes) relative to the HC class DBE 10 group (radical ions; likely sum of alkylated phenanthrenes). It appears that this proxy is mirroring the “DBT/P ratio” obtained from GC–MS data over a much broader range of molecular masses up to approximately 1000 Da. The other proxy is based on the observed differences between the O₁ class DBE 4 group and the N₁S₁ class DBE 14 group. Whereas oils derived from the siliciclastic source rocks show higher concentrations of the O₁ class, oils originated from the carbonate source units are enriched in the N₁S₁ species. Finally, published FTICR-MS data (APPI–P) from both oil source types with varying levels of maturation and biodegradation are included, in order to verify the robustness of the proposed proxies.

本研究的范围是开发受其他地球化学过程（如成熟度和生物降解）影响较小的可靠岩相代理。在这里，使用傅立叶变换离子回旋共振质谱 (FTICR-MS) 研究了来自不同石油环境的碳酸盐和硅质碎屑烃源岩的原油，从而提供有关沉积环境在控制碳氢化合物化学成分方面的作用的信息。碳酸盐油属于加拿大西部沉积盆地（WCSB），硅质碎屑油主要采自奥地利的莫拉塞盆地和奥地利维也纳盆地。化学成分的变化，使用 FTICR-MS 在两种不同电离模式下的数据详细讨论了两种油中主要化合物类别的芳香性和烷基化度：负离子模式下的电喷雾电离 (ESI-N) 和正离子模式下的大气压光电离(APPI-P)。从两种电离模式获得的结果表明酸性成分的化合物分布，例如纯氧成分（O₁至 O ₄类）和 N ₁ S ₁类，以及碳酸盐油中的硫和烃类物质与硅质碎屑岩产生的油类明显不同。最有可能的是，观察到的差异归因于相应烃源岩的沉积环境，因为其他过程（如热成熟和生物降解）的影响通过选择具有可比成熟水平的非生物降解油来减轻。计算的镜质反射率 (%R c) 在大多数选定的油品中，范围在 0.5 到 0.8 之间。观察到的碳酸盐和硅质碎屑油的化学成分差异导致基于 S ₁和 HC 物种（来自 APPI-P）以及 O ₁和 N ₁ S ₁类（来自ESI-N)。前一个代理是 S ₁的比率DBE 9 类基团（自由基离子；可能是烷基化二苯并噻吩的总和）相对于 HC 类 DBE 10 基团（自由基离子；可能是烷基化菲的总和）。似乎该代理反映了从 GC-MS 数据中获得的“DBT/P 比率”，其分子量范围更广，可达约 1000 Da。另一个代理基于观察到的 O ₁类 DBE 4 组和 N ₁ S ₁类 DBE 14 组之间的差异。源自硅质碎屑源岩的油显示出较高的 O ₁类浓度，而源自碳酸盐源单元的油富含 N ₁ S ₁物种。最后，包括来自具有不同成熟度和生物降解水平的两种油源类型的已发布 FTICR-MS 数据 (APPI-P)，以验证所提议代理的稳健性。