The effect of lamina and lithofacies assemblage on molecular maturity of oil in a shale source-rock reservoir
文献类型：期刊论文
| 作者 | Ma, Weijiao1,2; Cao, Yingchang1; Xi, Kelai1; Lin, Miruo1; Liu, Jinzhong2; Wang, Yunpeng2 |
| 刊名 | INTERNATIONAL JOURNAL OF COAL GEOLOGY
 |
| 出版日期 | 2023-11-01 |
| 卷号 | 279页码:12 |
| 关键词 | Hybrid shale system Lithofacies assemblage Hydrocarbon expulsion Molecular composition Molecular thermal maturity |
| ISSN号 | 0166-5162 |
| DOI | 10.1016/j.coal.2023.104373 |
| 英文摘要 | This paper discusses the effect of the source rock-reservoir assemblage and the assemblage-induced variability in hydrocarbon expulsion and the subsequent molecular composition as well as molecular thermal maturity within a hybrid shale system. The characterization work was conducted on lithofacies and microlamina scales using core samples from the Chang 73 sub-member of the Triassic Yanchang Formation in the Ordos Basin, China. Samples were collected from a narrow interval with a depth range of less than 15 m, and the main characterization work was performed by Rock-Eval pyrolysis and GC-MS analysis. The results show that chemical fractionation of preferential expulsion and migration of the saturated fraction exists in the source rock-reservoir assemblages at both the lithofacies and lamina scales. However, the molecular composition behaves differently at the lithofacies and lamina scale's source rock-reservoir assemblages, in which EC21_/EC22+ is higher in lamina scale reservoir but lower in lithofacies scale reservoir. It is assumed that the low-molecular weight n-alkanes also follow mo-lecular fractionation. The lithofacies reservoir has a lower EC21_/EC22+ because of the strong storage capacity of the laminated micro-reservoir within shale, which prevents the newly generated lighter oil from being charged into the lithofacies reservoir. The variation trends of thermal maturity indices Ts/hopane, the relative pregnane content, and TA(I)/TA(I + II) ratios, which have the same chemical basis with EC21_/EC22+, carry the same maturity signature as EC21_/EC22+. The above profile of the molecular composition and molecular-derived thermal maturity parameters indicate that within the short interval of a shale system where no differences in thermal maturity are expected, chain scission reactions and their derived thermal maturity indicators are very sensitive to source rock and reservoir. In addition, within a shale system, oil is more easily to expel out from the organic-rich lithofacies that are interbedded with organic-lean lithofacies. Oil expulsion may promote both chain cracking of oil and subsequently kerogen decomposition. This may provide geological evidence to explain why the frequent-stacking assemblage of source rock and reservoir lithofacies in a hybrid shale system is an ideal target for shale oil exploration. |
| WOS研究方向 | Energy & Fuels ; Geology |
| 语种 | 英语 |
| WOS记录号 | WOS:001094344100001 |
| 源URL | [http://ir.gig.ac.cn/handle/344008/78840]  |
| 专题 | 有机地球化学国家重点实验室 |
| 通讯作者 | Cao, Yingchang; Wang, Yunpeng |
| 作者单位 | 1.China Univ Petr East China, Natl Key Lab Deep Oil & Gas, Qingdao 266580, Peoples R China 2.Chinese Acad Sci, Guangzhou Inst Geochem, State Key Lab Organ Geochem, Guangzhou 510640, Peoples R China |
| 推荐引用方式 GB/T 7714 | Ma, Weijiao,Cao, Yingchang,Xi, Kelai,et al. The effect of lamina and lithofacies assemblage on molecular maturity of oil in a shale source-rock reservoir[J]. INTERNATIONAL JOURNAL OF COAL GEOLOGY,2023,279:12. |
| APA | Ma, Weijiao,Cao, Yingchang,Xi, Kelai,Lin, Miruo,Liu, Jinzhong,&Wang, Yunpeng.(2023).The effect of lamina and lithofacies assemblage on molecular maturity of oil in a shale source-rock reservoir.INTERNATIONAL JOURNAL OF COAL GEOLOGY,279,12. |
| MLA | Ma, Weijiao,et al."The effect of lamina and lithofacies assemblage on molecular maturity of oil in a shale source-rock reservoir".INTERNATIONAL JOURNAL OF COAL GEOLOGY 279(2023):12. |
入库方式： OAI收割
来源：广州地球化学研究所
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