南海北部深水区盆地烃源条件和油气源

南海北部深水区在古近纪经历了多幕裂陷作用，至新近纪开始进入坳陷阶段。裂陷期发育湖相和海陆过渡相烃源岩，坳陷期发育海相烃源岩，其中海陆过渡相烃源岩是南海北部深水区的主要烃源岩。南海北部深水区已发现的油气主要来源于海陆过渡相的崖城组和恩平组，海相的珠海组烃源岩对珠二坳陷深水区原油有重要贡献。琼东南盆地深水区天然气属于典型的煤型气，主要气源岩为崖城组腐殖型烃源岩;而珠二坳陷天然气既非典型的煤型气，也非典型的油型气，而是二者之间过渡类型天然气，气源岩为恩平组腐殖-腐泥混合型烃源岩。

Hydrocarbon source conditions and origins in the deepwater area in the northern South China Sea

The deepwater area of the northern South China Sea underwent multistage rifting in Paleogene and came into depression stage in Neogene. Lacustrine and transitional source rocks were formed mainly in the rifting period, while marine source rocks developed mainly in the depression stage. The transitional source rock is one of major source rocks in the deepwater area of the northern South China Sea．Oil and gas found in the northern South China Sea are mainly generated from transitional source rocks of Yacheng Formation and Enping Formation, while Zhuhai Formation marine source rock makes an important contribution to oil in the deepwater area of the Zhu II Depression. Natural gas in the Qiongdongnan deepwater area is a typical coal-type gas generated from Yacheng Formation humic source rock, but gas in the ZhuⅡ Depression of the Pearl River Mouth Basin is neither a typical coal-type gas nor an oil-type gas, instead it is a transitional gas generated from Enping Formation humic-sapropel source rock.