苏北盆地高邮凹陷始新统剥蚀厚度恢复

苏北盆地晚始新世至渐新世的三垛运动使得盆地构造沉降停止，盆地断陷发育期结束.发生了18x106a的沉积间断地层遭受强烈剥蚀,缺失上始新统和渐新统。利用储集层盐水包裹体均一-温度、粘土矿物、镜质体反射率和甾烷成熟度参数分析了高邮凹陷该构造运动期的不均衡剥蚀作用。自深凹带向斜坡带断阶带和低凸起，剥蚀作用渐次增强。采用声波时差法和镜质体反射率正演数值模拟法恢复了该期剥蚀厚度。二者的计算结果较吻合。该期总的剥蚀厚度为400~1 600m,其中.深凹带400~-600m.斜坡带500~1 200m .断阶带和低凸起1000~1 600m.这一-计算结果较以往的定性估计值要大这对重新认识该区的埋藏史热史。油气成藏史以及油气藏分布规律具有重要意义。

Restoration of Eocene Erosion Thickness in Gaoyou Sag

The tectonic subsidence of Subei basin ceased during Sanduo movement from Late Eocene to Oligocene. It had broughtabout the end of faulting growth in it and depositional break for 18Ma, with strong uplifting,erosion and absence of UpperEocene and Oligocene. The imbalanced erosion of Gaoyou sag is analyzed by the data of homogeneous temperature, clay mineral,vitrinite reflectance and C29-20S/(20S+20R) sterane ratio. It is shown that the erosion becomes stronger gradually from deep sagzone to slope zone,fault terrace zone and low uplift. The erosion thickness is estimated by the method of interval transit timeand forward numerical simulation of vitrinite reflectance. The results of them coincide with each other. The total erosion thicknessis about 400~1 600 m, where deep sag zone is of 400~600 m, slope zone of 500~1 200 m, fault terrace zone and low uplift of1 000~1 600 m in total. Such estimated values are bigger than previous results of qualitative estimation, which mean that renewalstudies should be made in the burial history, geothermal history, hydrocarbon accumulation history and oil-gas reservoir distributionn Gaoyou sag.