碳同位素分馏效应对深层原油来源判识的影响
作者:
作者单位:

作者简介:

王学军(1966—),男,山东荣成人,正高级工程师,博士,从事油气勘探综合研究。E-mail:wangxuejun977.slyt@sinopec.com。

通讯作者:

基金项目:

国家科技重大专项“渤海湾盆地精细勘探关键技术”下属课题“渤海湾盆地剩余油气资源潜力研究”(2016ZX05006-001),中国石化 油气勘探开发重大项目“东部富油气凹陷及周缘资源评价”(P23234)。


Influences of carbon isotope fractionation effects on identification of deep crude oil sources
Author:
Affiliation:

Fund Project:

  • 摘要
  • |
  • 图/表
  • |
  • 访问统计
  • |
  • 参考文献
  • |
  • 相似文献
  • |
  • 引证文献
  • |
  • 资源附件
    摘要:

    深层烃源岩演化程度高,随成熟度升高,原油中生物标志化合物含量大幅度减少,影响了利用常规生物标志化合物参数 进行油源对比的可靠性。针对如何更好地利用δ13CPDB值进行深层原油来源判识,通过渤海湾盆地济阳坳陷东营凹陷烃源岩自然演化剖面中可溶有机质、烃源岩生排烃物理模拟实验产物4 种族组分δ13CPDB值的分析,结合烷烃质量分数特征,探讨了深层烃源岩原油碳同位素分馏效应,提出利用δ13CPDB值进行深层原油来源判识的工作思路和方法。深层烃源岩因高热演化程度而产生的碳同位素分馏效应是明显的,烃源岩可溶有机质的烷烃、芳烃、非烃和沥青质4 种族组分δ13CPDB值随埋深的增加均发生了明显增大现象,其中烷烃δ13CPDB值变化最明显,达5‰ 以上,芳烃δ13CPDB值约为4‰,非烃和沥青质δ13CPDB的变化相对较小,约为2‰~3‰。随埋深的增加可溶有机质中烷烃质量分数由40%左右增至80%以上,相应烷烃δ13CPDB值由-30‰ 左右增至-24‰以上,且烷烃质量分数与其δ13CPDB值的变化有很好相关性。同一类型烃源岩样品生排烃物理模拟产物族组分δ13CPDB值也显示了相似的结果,烷烃δ13CPDB值的变化幅度最大可达4‰,而芳烃、非烃、沥青质的δ13CPDB值变化相对较小,约为1‰~3‰。利用碳同位素进行深层原油来源判识时,首先根据烷烃质量分数与烷烃δ13CPDB值的相关性判断是否存在热演化造成的碳同位素分馏效应,并对烷烃δ13CPDB值进行合理恢复,然后再利用恢复后的δ13CPDB值进行原油来源的合理判识。依照上述方法对准噶尔盆地西缘车排子凸起轻质油来源进行了判识,轻质油的碳同位素明显存在热演化造成的分馏效应,轻质油源自深部二叠系高成熟烃源岩的可能性很大,这对该地区油气勘探目标评价部署工作具有重要实践意义。

    Abstract:

    Deep source rocks undergo high degrees of evolution, leading to a significant decrease in biomarker content in crude oil as maturity increases. The decrease affects the reliability of the oil source correlation with conventional biomarker parameters. To better use the δ13CPDB value for identifying deep crude oil sources, authors analyzed the δ13CPDB values of four group components in the soluble organic matter from naturally evolved source rock profiles in Dongying Sag, Jiyang Depression, Bohaiwan Basin and the products of physical experiments on hydrocarbon generation and expulsion. Considering the relative content of alkane, authors discussed the carbon isotope fractionation effects in the crude oil from deep source rock. Additionally, authors proposed the working thought and procedure for identifying the source of deep oil with the δ13CPDB values. The carbon isotope fractionation effects resulting from high thermal maturity are obvious in deep source rocks. The δ13CPDB values of the four group components of soluble organic matter from source rocks (alkane, aromatics, non-hydrocarbon, and asphaltene) exhibit a significant elevation with increasing burial depth. Specifically, the δ13CPDB values of alkane exhibit the most pronounced change, exceeding 5‰, while aromatics show a change of around 4‰. The changes in the δ13CPDB value of non-hydrocarbon and asphaltene are relatively small, ranging from 2‰ to 3‰. As burial depth increases, the alkane contents in soluble organic matter increase from around 40% to over 80%. Correspondingly,the δ13CPDB values of alkane increase from around ?30‰ to over ?24‰, and the alkane contents show a great correlation with the variations of its δ13CPDB values. Similar results can also be observed from the δ13CPDB values of group components from physical experiments on hydrocarbon generation with the same type of source rock samples. In these experiments, the variations in the δ13CPDB values of alkane can reach 4‰, while those in aromatics, non-hydrocarbon, and asphaltene are relatively low, ranging from 1‰ to 3‰. When utilizing carbon isotopes to identify the source of deep oil, it is essential to first check the correlation between alkane contents and their δ13CPDB values to identify if the carbon isotope fractionation effects derived from thermal maturation exists.Subsequently, the δ13CPDB values of alkane should be properly recovered before utilizing it to identify the source of the oil. According to the abovementioned methods, authors identified the source of light oil from Chepaizi Uplift in the Western region of Junggar Basin. It confirmed the presence of carbon isotope fractionation effects in the light oil derived from thermal evolution. It shows a great possibility that the light oil is sourced from the underlying high-maturity source rock of the Permian, which is of important practical significance in the evaluation and deployment of the petroleum exploration target in this area.

    参考文献
    相似文献
    引证文献
引用本文

王学军,张学军,罗欢,王茹,林璐,翟正,康元勇.碳同位素分馏效应对深层原油来源判识的影响[J].油气地质与采收率,2024,31(4):154~163

复制
分享
文章指标
  • 点击次数:
  • 下载次数:
历史
  • 收稿日期:2023-12-12
  • 最后修改日期:2024-03-12
  • 录用日期:
  • 在线发布日期: 2024-08-12
×
《油气地质与采收率》
《油气地质与采收率》启动新投稿网站的公告