Migration differentiation of hydrocarbon components in the 7th member of the Triassic Yanchang Formation，central Ordos Basin

被引：0
|
作者：
Shi L. [1 ]
Fan B. [1 ]
Li Z. [1 ]
Yu Z. [2 ]
Lin Z. [1 ]
Dai X. [1 ]
机构：
[1] School of Petroleum Engineering and Environmental Engineering, Yan’an University, Shaanxi, Yan’an
[2] No. 3 Oil Extraction Factory, Qinghai Oilfield Company, PetroChina, Mangya, Qinghai
来源：
Oil and Gas Geology | 2024年 / 45卷 / 01期
关键词：
Chang 7 Member of Yanchang Formation; hydrocarbon component; migration differentiation; Ordos Basin; shale; Triassic;
D O I：
10.11743/ogg20240111
中图分类号：
学科分类号：
摘要：
The shale sequence of the 7th member of the Yanchang Formation（also referred to as the Chang 7 Member）in the Ordos Basin consists of mudstones，shales，and sandstones. To delve into the migration differentiation of shale oil components in different lithologies，we investigate the migration differentiation of typical hydrocarbon components in the central Ordos Basin. The findings show that the rocks exhibit different contents of the four group components：saturated hydrocarbons（SAT），aromatic hydrocarbons（ARO），polar nitrogen- ，sulfur- ，and oxygen-containing compounds （NSO），and asphaltenes（Asph）. Specifically，the sandstones manifest high SAT content and low NSO+Asph content. Conversely，the shales and mudstones exhibit low SAT content and high NSO+Asph content. Regarding n-alkanes，the sandstones demonstrate high nC11-15 content and low nC23-39 content，while the shales and mudstones display low nC11-15 content and high nC23-39 content. Compared to the sandstones，the shales and mudstones show more significant variations in the Pr/Ph，Pr/nC17，and Ph/nC18 ratios. These rocks manifest low C27/C29 regular sterane ratios and low Ts/Tm and Ts/ （Ts+Tm）ratios，while the sandstones show opposite trends. They demonstrate substantial variability in 22S（/ 22S+22R）ratios for C32 homohopane，in contrast to the relatively concentrated ratios for the sandstones. Besides，the sandstones are characterized by high gammacerane index values varying in a broad range，whereas the shales and mudstones exhibit the opposite trend. Notably，the shales and mudstones generally have 8β（H）-drimane/8β（H）-homodrimane ratios exceeding 1，which，however，are typically less than 1 for the sandstones. A comprehensive analysis indicates that the variations in the distributions of the various hydrocarbon group components within the source rocks can be attributed to both differential adsorption and migration differentiation. © 2024 Editorial Department of Oil and Gas Geology. All rights reserved.
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页码：157 / 168
页数：11
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共 29 条
  • [11] CHEN Zhonghong, ZHA Ming, Geological and geochemical characteristics of hydrocarbon-expulsion from source rocks in Dongying Depression［J］, Geochimica, 34, 1, pp. 79-87, (2005)
  • [12] HILL R J，, RUBLE T E，, Et al., Unconventional shale-gas systems：The Mississippian Barnett Shale of north-central Texas as one model for thermogenic shale-gas assessment ［J］, AAPG Bulletin, 91, 4, pp. 475-499, (2007)
  • [13] MA Wei, LI Jian, WANG Dongliang, Et al., Hydrocarbon expulsion efficiency of source rocks and its influencing factors［J］, Natural Gas Geoscience, 27, 9, pp. 1742-1751, (2016)
  • [14] WANYAN Ze, LONG Guohui, YANG Wei, Et al., Hydrocarbon accumulation and evolution characteristics of Paleogene in Yingxiongling area，Qaidam Basin［J］, Lithologic Reservoirs, 35, 2, pp. 94-102, (2023)
  • [15] ZHANG Jingkun, CAO Jian, SHI Chunhua, Et al., Evaluating novel trace element proxies for oil-source rock correlations［J］, Chinese Science Bulletin, 68, 10, pp. 1247-1265, (2023)
  • [16] FAN Bojiang, SHI Liang, YANG Jie, Et al., Sedimentary environment of lacustrine organic matter in the central Ordos Basin ［J］, Oil & Gas Geology, 43, 3, pp. 648-657, (2022)
  • [17] ZHANG Yaxiong, Source rock characterization： The dark mudstone in Chang 7 Member of Triassic，central Ordos Basin ［J］, Oil & Gas Geology, 42, 5, pp. 1089-1097, (2021)
  • [18] FAN Bojiang, JIN Yue, SHI Liang, Et al., Shale oil exploration potential in central Ordos Basin：A case study of Chang 7 lacustrine shale［J］, Oil & Gas Geology, 42, 5, pp. 1078-1088, (2021)
  • [19] YOUNG A, MCIVER R D., Distribution of hydrocarbons between oils and associated fine-grained sedimentary rocks—physical chemistry applied to petroleum geochemistry， II［J］, AAPG Bulletin, 61, 9, pp. 1407-1436, (1977)
  • [20] LEYTHAEUSER D，, MACKENZIE A，, SCHAEFER R G，, Et al., A novel approach for recognition and quantification of hydrocarbon migration effects in shale-sandstone sequences［J］, AAPG Bulletin, 68, 2, pp. 196-219, (1984)
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