柴达木盆地北缘侏罗系两类不同有机质丰度泥岩的 生物标志物特征对比研究
- 中国石油青海油田公司勘探事业部 甘肃 敦煌 736202
- 收稿日期:
1900-01-01
- 修回日期:
1900-01-01
- 刊出日期:
2008-08-10
摘要: 在柴达木盆地北缘地区,分别选取有机碳含量很低和较高的侏罗系泥岩样品,对比分析了它们在生物标志物组成上的差异。结果发现,高有机质丰度泥岩的生标组成与我国西北地区侏罗纪煤系有机质的特征差异不大,相比而言,低有机质丰度泥岩的正烷烃以前主峰为特征,Pr/Ph比值在1.0左右,三环萜烷和伽马蜡烷丰度较高,并在部分样品中检出了25降藿烷系列。结合泥岩的有机岩石学特征,认为这些差异可能反映了泥岩沉积环境和生烃母质的不同:高有机质丰度泥岩的有机显微组分以相对弱还原条件下的形态有机质为主,包括藻类体、孢子体和角质体等,而低有机质丰度泥岩的有机显微组分以相对强还原条件下的矿物沥青基质为主,其母质可能来源于低等显微菌藻类。进一步通过对比不同有机质丰度泥岩,以及区内原油生标组成之间的相互关系,讨论了研究区的油源问题。
Contrasting Biomarker Features of Two Types of Jurassic Mudstones with Different Organic Matter Contents in the Northern Qaidam Basin
- PetroChina Qinghai Oilfield Company, Branch of Petroleum Exploration, Dunhuang, Gansu 736202
- Received Date:
1900-01-01
- Rev Recd Date:
1900-01-01
- Publish Date:
2008-08-10
Abstract: Two types of Jurassic mudstones with different total organic contents (TOC) from the northern Qaidam Basin were analyzed for biomarker features in this study. It is showed that these two types of mudstones have pronounced different biomarker compositions. The mudstones with high TOC contents show similar features to other Jurassic source rocks and their derived oils in the western China’s Jurassic petroliferous basins. In contrast, as to the mudstones with low TOC contents, it is characterized by an nalkane envelope that peaks at a low carbon number (e.g., nC16, nC17), Pr/Ph around 1.0, abundance of tricyclic terpane and gammacerane, and detection of 25norhopane series in two samples. Combined with organic petrographic features of mudstones, it is implied that the biomarkers reflect depositional environments and bioprecursors of the mudstones. Bioprecursors of high TOC mudstones consist mainly of algae, cutinites and sporophytes, under relatively anaerobic situations. As to the low TOC mudstones, organic maceral composition is composed mainly of mineral bituminous matrix, which comes from biodegradation of microalga by microbe under relatively more anaerobic conditions. Furthermore, based on a comparison between biomarkers of mudstones analyzed in this study and of presently explored oils, the oil source in the study area was discussed.
杨少勇. 柴达木盆地北缘侏罗系两类不同有机质丰度泥岩的 生物标志物特征对比研究[J]. 沉积学报, 2008, 26(4): 688-696.
引用本文: |
杨少勇. 柴达木盆地北缘侏罗系两类不同有机质丰度泥岩的 生物标志物特征对比研究[J]. 沉积学报, 2008, 26(4): 688-696.
|
YANG Shao-yong. Contrasting Biomarker Features of Two Types of Jurassic Mudstones with Different Organic Matter Contents in the Northern Qaidam Basin[J]. Acta Sedimentologica Sinica, 2008, 26(4): 688-696.
Citation: |
YANG Shao-yong. Contrasting Biomarker Features of Two Types of Jurassic Mudstones with Different Organic Matter Contents in the Northern Qaidam Basin[J]. Acta Sedimentologica Sinica, 2008, 26(4): 688-696.
|