南海北部陆缘晚期油气成藏机理及动力学过程

总结了南海北部陆缘晚期(或浅层)油气藏的勘探技术和方法,指出晚期油气成藏具有海底麻坑、气烟囱、"地震模糊带"和"亮点"等地震异常特征,从地化特征上可划分为浅层生物气、成熟—高成熟热解气和高含CO2热解气等3种油气成藏类型.在研究新构造运动表现形式的基础上,分析了逆断层、正断层和底辟—走滑断层3个断层活动区的晚期油气成藏机理,指出断层晚期活动和后期快速沉降促进了油气的运移和再分配,晚期油气成藏主要沿莺歌海盆地莺东斜坡带、东方—乐东区和沿琼东南盆地二号断裂带及珠江口盆地坳陷边缘斜坡带等分布,有利于油气和天然气水合物的勘探.

LATE HYDROCARBON ACCUMULATION MECHANISM AND DYNAMICS OFFSHORE THE NORTHERN SOUTH CHINA SEA

Exploration technologies and methods for late hydrocarbon accumulations offshore the northern South China Sea have been summarized in this paper.The late hydrocarbon accumulations are cha-racterized by seismic anomalies such as bottom caves,gas chimneys,"obscure seismic area" and "bright points".Based on geochemical features,three types of accumulations can be identified: biogas in sha-llow layer,mature-highly mature gas and thermal gas with high CO2 content.According to neotectonism,late dynamics of petroleum systems related to thrust fault,normal fault as well as diapire-structure and strike-fault have been analyzed.The late movements of faults and the fast thermal subsidence have promoted hydrocarbon migration and redistribution with series of petroleum accumulation distributed along Yingdong ramp and Dongfang-Ledong area in the Yinggehai Basin,No.2 fault zone in the Qiongdongnan Basin and edge ramps of depressions in the Pearl River Mouth Basin.It contributes to the exploration of hydrocarbon and hydrate offshore the northern South China Sea.