摘要
本文研究了我国塔里木盆地上石炭统海相碳酸盐地层中的晶洞油苗和下奥陶统灰岩裂隙中沥青脉的生物标志化合物特征。上石炭统生物灰岩晶洞中的液体油苗成熟度较高,具低姥植比,正构烷烃偶数碳优势,高碳数藿烷丰度较高,αβ-C_(35)藿烷略大于αβ-C_(34)藿烷等特征。这可与围岩的生物标志化合物相类比。下奥陶统灰岩裂隙中的沥青脉,其生物标志化合物主要由25-降藿烷、8,14-断藿烷以及D环芳构化8,14-断藿烷等系列化合物组成。沥青脉芳烃的去甲基化作用也异常强烈。菲系列化合物中,菲含量为72.5％。资料表明,沥青脉可能来源于盆地深部储集层中的原油,曾经历过较高的地热作用,运移至浅层后又遭受到微生物降解和氧化等作用而形成。这为评价盆地深部的含油气性提供了重要信息。
This paper centers on the study of the marker characteristics of vug seepages which are from marine carbonate of the upper Carboniferous in Tarim Basin. The results show that the liquid seepage, collected from biogenic limestone, has a higher thermal maturity, a lower pristane-to- (Pr/Ph) ratio, a slight even to odd dominance in the n-alkanes,. a high content of higher molecular weight hopanes, and a slightly higher abundance of 17α. (H) 21 β (H) -C35 hopane relative to 17α (H) 21β(H) -C34 hopane. All of those have a good correlation with extract of the surrounding rocks, which indicates that the vugs seepage was autochthonous.
The paper has also studied on the geochemical characteristics of the asphalt veins in the limestone fissures of the lower Ordovician in the basin. It is proved that the biomarkers of as- phalt veins are mainly composed of 25-nor hopanes, 8, 14-secohopanes and ring-D-aromatic 8, 14- secohopanes; and the aromatics of asphalt veins have a intensive demethylized career; Phenanthren in it takes a percentage of 72.5 in phenanthrenoids. Obviously by analysing the geologic information, the asphalt was formed by the material originated from the crud oil of the deep part in the basin, underwent a higher geothermal alteration and the microbial-biodegradation and oxidation .
It is obivous that the result mentioned above may provied important information for the assessment of petroleum prospect in the deep part of the basin.
出处
《沉积学报》
CAS
CSCD
北大核心
1990年第4期104-114,共11页
Acta Sedimentologica Sinica
