膏盐沉积盆地中未成熟高硫原油的发现及意义

DISCOVERY OF IMMATURE HIGH SULFUR CRUDE OIL AND ITS SIGNIFICANCE IN GYPSUM-SALT BEARING SEDIMENTARY BASIN

江继纲 盛国英 傅家谟

Jiang Jigang Sheng Guoying Fu Jiamo

石油工业部, 江汉石油勘探开发研究院 2. 中国科学院, 地球化学研究所

Jianghan Research Institute of Petroleum Exploration and Development, Ministry of Petroleum Industry 2. Research Institute of Geochemistry, Academia Sinica

江汉膏盐沉积盆地中板1井浅层610.23—658.5m发现的未成熟高硫重质原油,其基本特征是:低饱和烃、高非烃:正烷烃具有极明显的偶奇优势;特别富含植烷、伽玛蜡烷、镍卟啉与丰富的长链烷基噻吩类和四氢化噻吩类等生物标记化合物。烷基噻吩和烷基四氢化噻吩类化合物也呈现出极明显的偶奇优势。根据原油产出的地质构造和岩性组合条件以及原油的生物标志物特征综合判断,此原油属典型的自生自储未成熟油,原油的成熟度大致相当于Ro为0.36%。板1井未成熟高硫重质原油的生成主要与膏盐强还原环境,尤其是特别高的含硫量有关。

Immature high sulfur heavy crude oil is discovered in Bang 1 Well at depth of 610.23-658.5 m in Jianghan gypsum-salt bearing basin.The principal characters of the crude oil are of low content of saturated hydrocarbons,high content of non-hydrocarbons and remarkable even-odd predominance in n-alkyl hydrocarbons.It is particularly rich in the biomark-ers,such as phytane,gamma cerane,nicked porphyrin,and long-chain alkyl thiophene,tetrahydrothiophene,etc.The alkyl thiophene and alkyl tetrahydrothiophene also have an obvious even-odd predominance.The original configuration of biologic materials is ref lectedin strerane distribution.Based on the geological structure and lithologic characters of the occurrence of the crude oil,as well as biomarkers,it is concluded that such a crude oil can be assigned to immature oil generated and accumulated in situ.Its maturity corresponds to the value of Ro0.36%.Certainly,the generation of such an immture heavy crude oil with high content of sulfur could be related to the source rocks rich in sapropelic organic material at shallow depth and low temperature.However,the more decisive factor controlling its generation may be the strong reduction environment of gypsum-salt with high content of sulfur.

国家自然科学基金项目(850303);中国科学院有机地球化学开放研究实验室项目(OGL85—02)

https://doi.org/10.11781/sysydz198804337