云南景谷盆地第三系化石颜色变化与有机质成熟度的关系

COLOUR ALTERATION OF FOSSIL POLYPODIISPORITES AND MATURATION OF THE ORGANIC MATTER OF JINGGU BASIN

李元美 夏开华

Li Yuanmei Xia Kaihua

滇黔桂石油地质科学研究所 昆明

Dian-Qian-Gui Institute of Petroleum Geology, China's General Corporation of Petroleum and Natural Gas

Polypodiisporites化石在云南新生代地层中广泛分布,找到了它的颜色变化与有机质成熟度的关系,就可以直接利用它来推测石油的形成与演化,找油找气的有利范围和层位。在同一样品中,Polypodiisporites化石的颜色比不同类型的孢粉统计出的颜色暗一级左右,而它们共同所经受过的古地温是相同的。在景谷盆地第三纪地层中,Polypodiisporites化石的颜色为黄—桔黄色的层段,颜色指数为2.6—3.0,有机质镜质体反射率为0.42%,古地温小于60℃,有机质未成熟。Polypodiisporites化石的颜色为棕—黑色的层段,颜色指数为3.5—5.9,镜质体反射率为0.58—0.8%,古地温在60—110℃,有机质已成熟,生油潜力最大。本文还讨论了孢粉化石的颜色与有机质含量多少的关系。

The relationship between colours of fossil Polypodiisporites,a widespread fossil spore in Cenozoic of Yunnan, and the maturation of organic matter could be employed to infer the stages of petroleum generation and evolution, and to indicate the favourable horizons and areas for petroleum prospecting. The study indicates that the colour of Polypodiisporites can be darker one grade over that of other sporo-pollen within the same rock specimen, though they all were subjected to the same palaeotemperature.For the Tertiary of the Jinggu Basin, the relationship between the colour of Polypodiisporites and the organic matter maturity is as follows. For yellow-orange section, the colour index ranging from 2.6-3.0, corresponding to vitrinite reflectance 0.42% and palaeotemperature of less than 60℃, indicates an immature stage of organic matter. The brown-black section, colour index 3.5-5.9, reflectance 0.58-0.8%, palaeotemperature 60-110℃, indicates the mature stage with the greatest potential of oil-generation. The effects of the amount of organic matter on the colour of sporo-pollen have also been discussed in the paper.

https://doi.org/10.11781/sysydz199002206