Characteristics of Overpressure Systems and Their Significance in Hydrocarbon Accumulation in the Yinggehai and Qiongdongnan Basins,China
  • 【DOI】

    10.3321/j.issn:1000-9515.2003.02.014

  • 【摘要】

    Overpressure systems are widely developed in the central depression and paleo-uplift in the Yinggehai and Qiongdongnan basins. They can be divided into three types according to the origin of abnormall... 展开>>Overpressure systems are widely developed in the central depression and paleo-uplift in the Yinggehai and Qiongdongnan basins. They can be divided into three types according to the origin of abnormally high formation pressure in the reservoirs, i.e. the autochthonous, vertically-transmitted and laterally-transmitted types. The autochthonous overpressure system results from rapid disequilibrium sediment loading and compaction. In the allochthonous overpressure system, the increase of fluid pressure in sandstone originates from the invasion of overpressured fluid flowing vertically or laterally through the conduit units. The autochthonous overpressure system occurs in the deep-lying strata of Neogene age in the central depression of the Yinggehai and Qiongdongnan basins. The vertically transmitted overpressure system is developed in the shallow strata of Late Miocene and Pliocene ages in the diapiric zone of the central Yinggehai basin, and the laterally transmitted overpressure system occurs in the Oligocene strata of paleo-uplifts, such as the structure of Ya-211 in the Qiongdongnan basin. The results indicate that the autochthonous overpressure system is generally a closed one, which is unfavorable for the migration and accumulation of hydrocarbons. In the allochthonous overpressure system, hydrocarbon accumulation depends on the relationship between the formation of overpressure systems and the spatial location and duration of hydrocarbon migration. The interval overlying the overpressure system is usually a favorable hydrocarbon accumulation zone if the duration of fluid expulsion coincides with that of hydrocarbon accumulation. 收起<<

  • 【作者】

  • 【作者单位】

    Faculty of Earth Resources/Faculty of Earth Resources/China National Offshore Oil Nanhai West Corporation

  • 【刊期】

    地质学报(英文版) SCI 2003年2期

  • 【关键词】

    basin fluid  overpressure system  Yinggehai and Qiongdongnan basins  South China Sea 

  • 【基金项目】

    This study was supported by the Trans-century Training Programme Foundation for the Talents by the State Education Commission (now the Ministry of Education) of China and the key project 教育部科学技术研究项目