莺歌海盆地新近纪以来古构造地貌恢复

Restoration of Neogene paleo-geomorphology of Yinggehai Basin

新近系三亚组和梅山组是莺歌海盆地烃源岩发育的重要层系,研究其古构造地貌是预测烃源岩分布和油气资源潜力的基础。应用"构造应力体制保持不变的情况下,盆地内古构造地貌继承性发育"的思想,在确定莺歌海盆地新近纪构造变形应力体制及其演化的基础上,应用"将今论古"和"比例补偿"的思想和方法,分别以盆地现今地貌特征和地层厚度分布为基础资料,并以单井资料确定局部古海水深度作为约束条件,恢复莺歌海盆地新近纪的古构造地貌(古海水深度)。指出莺歌海盆地在三亚组和梅山组沉积时期是半封闭的局限海湾环境,有利于烃源岩的发育;提出古构造地貌研究的新方法——比例补偿法,可应用于其他盆地古构造地貌的恢复。

The Neogene Sanya and Meishan formations are important sequences of source rocks in the Yinggehai Basin.Understanding the paleo-tectonic geomorphology is an important basis for predicting the distribution of source rocks and the potential of oil and gas resources.Based on the rule that"the paleo-tectonic environment develops in the inherited way when tectonic stress system remains unchanged",we applied the idea and method of"the present is the key to the past"and"proportional compensation"to interpret the Neogene tectonic deformation system and its evolution in the Yinggehai Basin.The current geomorphological features and stratigraphic thickness distribution were used with the paleo-sea depth determined from single well data as a constraint to restore the Neogene paleo-geomorphology of the Yinggehai Basin.The Yinggehai Basin was a semi-enclosed confined bay during the deposition of the Sanya and Meishan formations,which was conducive to the development of source rocks.The"proportional compensation"method,which is a new way for paleo-geomorphology restoration,can be applied in other basins.