论文部分内容阅读
珠江口古湖是中国东部最大的早第三纪裂谷湖之一.在珠江口古湖发育的鼎盛期——始新世,湖面宽阔,湖水较深,湖泊具欠补偿沉积条件,其营养和浮游植物生产力都达到较高水平.含有丰富浮游藻类化石的文昌组暗色泥岩即形成于这一时期.文昌组浮游藻类相对丰度高,表明始新世珠江口古湖的表层水初始生产力高.这意味着古湖沉积物具有良好的富氢有机质物源条件.文昌组暗色泥岩有机相横向变化明显,表明始新世珠江口古湖湖底缺氧和充氧条件并存.形成于缺氧水体下的无定形有机相在盆地大部分地区均有发育,其TOC值和l_H值较高;反映充氧底部水环境的陆源植物有机相分布于HJ15-1-1井所在的盆地东部边缘,其TOC值和I_H值较低.具有无定形有机相的文昌组暗色泥岩是珠江口盆地良好的湖相油源岩.中国东部陆上和近海早第三纪盆地各凹陷的湖相油源岩发育差异甚大,其控制因素是由水体中溶解氧含量变化所造成的有机质保存条件的差异.富生油凹陷形成于缺氧的古湖区.
Pearl River Mouth The ancient lake is one of the largest Early Tertiary rift lakes in eastern China.At the peak of the ancient lake development in the Pearl River estuary, the Eocene, the lake is wide, the lake is deep, the lake has undercompensated deposition conditions, and its nutrition And phytoplankton productivity all reached a higher level.The Wenchang Formation dark mudstone with abundant phytoplankton fossils was formed during this period.The relative abundance of phytoplankton in Wenchang Formation is high, indicating that the initial productivity of surface water of the Paleocene Pearl River Mouth Lake is high .This implies that the ancient lake sediments have good hydrogen-rich organic matter source conditions.The Wenchang formation of dark mudstone has obvious lateral variation of organic facies, indicating that the hypoxia and oxygenation conditions coexist at the bottom of the ancient lake in the Eocene Pearl River. Under the amorphous organic phase in all parts of the basin are developed, the TOC value and l_H value higher; reflecting the oxygenated bottom water environment of terrestrial plant organic distribution in the HJ15-1-1 well where the eastern margin of the basin, the TOC value and I_H value are lower.The Wenchang Formation dark mudstone with amorphous organic phase is a good lacustrine source rock in the Pearl River Mouth Basin.The lacustrine source rocks in the sag of the Early Tertiary Basin in the eastern China and in the offshore are developed Very different The controlling factor is the difference of the preservation conditions of organic matter caused by the change of the dissolved oxygen content in the water.Fusen oil sags formed in the anoxic Lake Guhu.