Based on GC-MS testing data of many saturated hydrocarbon samples, 17α(H)-C30 diahopanes (C30*) are extensively distributed in the lacustrine hydrocarbon source rocks of the Yanchang Formation in Ordos Basin, but sho...Based on GC-MS testing data of many saturated hydrocarbon samples, 17α(H)-C30 diahopanes (C30*) are extensively distributed in the lacustrine hydrocarbon source rocks of the Yanchang Formation in Ordos Basin, but show remarkable differences in relative abundance among various source rocks. Generally, Chang 7 high-quality source rock (oil shale) developed in deep lake anoxic environment shows lower C30* content, whereas Chang 6-9 dark mudstone developed in shallow to semi-deep lake, sub-oxidizing environment shows relatively high to high C30* value. Particularly, Chang 7 and Chang 9 black mudstones in Zhidan region in the northeast of the lake basin show extremely high C30* value. A comparative analysis was made based on lithology, organic types and various geochemical parameters indicative of redox environment, and the results indicate that environmental factors such as redox settings and lithology are key factors that control the C30* relative abundance, while organic types and maturity may be minor factors. High to extremely high C30* values are indicative of sub-oxidizing environment of fresh-brackish water and shallow to semi-deep lake. Therefore, research on C30* relative content and distribution in lacustrine hydrocarbon source rocks in the Yanchang Formation, especially on the difference in C30* between Chang 7 high-quality source rocks (oil shale) and Chang 6-91 source rocks (dark mudstone), will provide an important approach for classification of Mesozoic lacustrine crudes and detailed oil-source correlation in the basin.展开更多
As triterpenoid biomarkers mainly derived from prokaryote （e.g. bacteria andcyanobacteria）, hopenoid hydrocarbons are ubiquitous in fossil fuels and sediments.Ensminger et al. （1974） reported a normal distribution...As triterpenoid biomarkers mainly derived from prokaryote （e.g. bacteria andcyanobacteria）, hopenoid hydrocarbons are ubiquitous in fossil fuels and sediments.Ensminger et al. （1974） reported a normal distributional pattern of C27-C35 (withoutC<sub>28</sub>) hopanes with an absolute predominance of C<sub>30</sub> hopane. In 1980, Seifert展开更多
基金Supported by National Natural Science Foundation of China (Grant No. 40773028)
文摘Based on GC-MS testing data of many saturated hydrocarbon samples, 17α(H)-C30 diahopanes (C30*) are extensively distributed in the lacustrine hydrocarbon source rocks of the Yanchang Formation in Ordos Basin, but show remarkable differences in relative abundance among various source rocks. Generally, Chang 7 high-quality source rock (oil shale) developed in deep lake anoxic environment shows lower C30* content, whereas Chang 6-9 dark mudstone developed in shallow to semi-deep lake, sub-oxidizing environment shows relatively high to high C30* value. Particularly, Chang 7 and Chang 9 black mudstones in Zhidan region in the northeast of the lake basin show extremely high C30* value. A comparative analysis was made based on lithology, organic types and various geochemical parameters indicative of redox environment, and the results indicate that environmental factors such as redox settings and lithology are key factors that control the C30* relative abundance, while organic types and maturity may be minor factors. High to extremely high C30* values are indicative of sub-oxidizing environment of fresh-brackish water and shallow to semi-deep lake. Therefore, research on C30* relative content and distribution in lacustrine hydrocarbon source rocks in the Yanchang Formation, especially on the difference in C30* between Chang 7 high-quality source rocks (oil shale) and Chang 6-91 source rocks (dark mudstone), will provide an important approach for classification of Mesozoic lacustrine crudes and detailed oil-source correlation in the basin.
文摘As triterpenoid biomarkers mainly derived from prokaryote （e.g. bacteria andcyanobacteria）, hopenoid hydrocarbons are ubiquitous in fossil fuels and sediments.Ensminger et al. （1974） reported a normal distributional pattern of C27-C35 (withoutC<sub>28</sub>) hopanes with an absolute predominance of C<sub>30</sub> hopane. In 1980, Seifert
