世界著名深水油气盆地的构造特征及对我国南海北部深水油气勘探的启示

Tectonic Features of World's Major Deep-water Oil/Gas Fields and Their Enlightenment to Deep-water Exploration in Northern South China Sea

介绍世界著名深水油气盆地的主要特征,着重构造特征,并与南海北部深水区进行了对比。世界著名深水油气盆地产出的大地构造条件具多样性,虽然大多数位于开阔大洋被动陆缘(南大西洋裂谷系、北海、澳大利亚西北陆架盆地),但边缘海的被动陆缘(墨西哥湾盆地)、转换大陆边缘(洛杉矶盆地)、主动陆缘(南沙海槽盆地)也可形成极佳的深水含油气盆地。南海北部深水区具有世界某些重要深水含油气盆地类似的特征,如位于被动陆缘和大河出口下方,以裂陷期的湖相富有机质页岩为主要生油岩,白云凹陷发育上下叠置的6层深水扇等,这都是有利的石油地质条件。但南海北部深水区盐层和盐构造不发育,构造圈闭相对较不发育,使深水油气系统的研究更加困难,也更具开拓意义。

Major features, especially tectonic features of world＇s famous deep-water oil/gas fileds are outlined, which demonstrated the structural diversity of hydrocarbon accumulation in deep-water environment. Although majority of giant fields are discovered in the passive continental margins of open oceans （e. g. the South Atlantic rift system, the North Sea, the NW Australia shelf）, giant and large fields have been found also in the passive continental margins of marginal seas （ e. g. the Gulf of Mexico）, transfer continental margins （ e. g. the Los Angeles basin）, and active convergent margins （e. g. the NW Borneo trough）. In comparison, the deep-water region of northern South China Sea shares some favorite features with respective world＇s famous deep-water fields, such as being located in passive continental margin and feed by a major river system, having organic-rich lacustrine shale as major source rocks, having overlapped layers of deep-water fans, etc. On the other hand, in the deep-water region of northern South China Sea no salt and salt tectonics, and structural traps are less developed. These put forward new challenge to the hydrocarbon exploration in deep-water northern South China Sea.