吐哈盆地台北凹陷西部油源浅析

PRELIMMINARY ANALYSIS ON THE OIL SOURCES OF THE WEST TAIBEI SAG IN THE TURPAN-HAMI BASIN

卫延召 戴金星 赵长毅

WEI Yan-zhao DAI Jin-xing ZHAO Chang-yi

中国石油勘探开发研究院, 北京 100083

Research Institute of Petroleum Exploration and Development, CNPC, Beijing 100083, China

吐哈盆地是我国唯一发现的一个油气以煤成油为主的盆地,其中台北凹陷是吐哈盆地的主体凹陷,也是发现油气最多的凹陷。以丘陵构造带为界,可将台北凹陷分为东西两部分。东部原油的特征具有典型的煤成油特征,西部原油的特征则界于湖相油和煤成油之间。从表面上看,西部原油特征具有混源特征,但从原油碳同位素、饱芳比、姥植比等指标的分布区间进行分析,西部原油这些指标值的分布区间明显小于东部原油。因此,西部原油不可能由湖相油和煤成油混合而成,而是由性质界于典型湖相泥岩和煤系源岩之间的中、下侏罗统湖相泥岩所生成。根据石油地质综合分析,胜北次凹的前侏罗系烃源岩并非台北凹陷西部原油的油源。

The Turpan-Hami Basin is the only one discovered in China whose hydrocarbon is dominated by coal related oil. The Taibei Sag is the major one of the basin, and is also the one in which the most amount of hydrocarbon is discovered. Having the hill tectonic zone as the boundary, the Taibei Sag can be divided into the west and the east two parts. The eastern crude oil has the typical characteristics of coal-related oil, and the characteristics of the western crude oil are between lake facies oil and coal related oil. To look at the surface, the western crude oil possesses the characteristics of mixed sources; but the analysis on the carbon isotope, the ratio of saturated and aromatic hydrocarbons and the ratio of pristane and phytane for crude oil shows that the distributive ranges of these indexes for the western crude oil are obviously small than those for the eastern crude oil. Therefore, the western crude oil cannot consist of lake facies oil mixed with coal-related oil; it may be formed in the Middle-Lower Jurassic lake facies mudstone whose features are between typical lake facies mudstone and coal measure source rocks. According to the comprehensive analysis of petroleum geology, the pre-Jurassic hydrocarbon source rocks in the Shengbei Subsag are not the oil sources of the western crude oil in the Taibei Sag.

石油科技青年创新基金(97-138).

https://doi.org/10.11781/sysydz200102191