中文摘要：

北部湾盆地是我国海域较早开展油气勘探的地区之一,已经历50多年的油气勘探历程。目前的油气勘探区块主要集中于涠西南、福山凹陷等局部地区,盆地整体勘探程度较低,勘探突破少。因此,加强雷东凹陷等后备区的地质研究与资源评价十分必要。分析了北部湾盆地雷东凹陷主控断裂的发育特征、演化规律及其形成机制,并探讨了其对沉积充填与油气运聚成藏的控制作用。北部湾盆地雷东凹陷3条主干断裂的活动对沉积相带分布的控制作用十分明显,形成了东、西2个次洼,次洼内各有2个沉降中心。东次洼北断裂和西次洼南断裂是受NW—SE向拉张作用形成的NE向伸展断层,而西次洼北断裂是具平移剪切断层性质的转换断层。始新世早期,西次洼南断裂活动强烈,西次洼北断裂、东次洼北断裂开始发育;始新世晚期,西次洼南断裂活动减弱直至停止,西次洼北断裂、东次洼北断裂持续活动直至渐新世晚期停止;中新世断裂不发育,整体为拗陷阶段。雷东凹陷油气勘探应从有利疏导体系评价着手,在凹中隆、南部斜坡、北部陡坡等有利的油气优势运聚区寻找突破。

英文摘要：

As one of the earliest offshore basins for oil and gas exploration in China,the Beibuwan Basin has experienced more than 50 years of oil and gas exploration.The current oil and gas exploration blocks are mainly located in some local regions,such as the Weixinan Sag,Fushan Sag and so on.The exploration density of the whole basin remains low.And no breakthrough has been made recently.Therefore,it is necessary to carry out more researches on geology and to make further resource evaluation in backup blocks,such as the Leidong Sag.In this paper,the characteristics as well as the evolution and formation mechanism of some major faults in the Leidong Sag are analyzed and their control over the sediment infilling and oil and gas accumulation discussed.There are three major faults in the region which control the distribution pattern of sedimentary facies and two sub-sags with individual depositional centers are formed.The North Fault in the Eastern Sub-sag and the South Fault in the Western Sub-sag are extensional in NE direction,influenced by NW-SE stretching stress,while the North Fault in the Western Sub-sag is a transform one characterized by transformation and shearing.In Early Eocene,the activity of the South Fault in the Western Sub-sag was intensified.The North Fault in the Eastern Sub-sag and the North Fault in the Western Sub-sag started to develop.In Late Eocene,the activity of the South Fault in the Western Sub-sag slowed down and eventually stopped.The North Fault in the Eastern Sub-sag and the North Fault in the Western Sub-sag kept active until late Oligocene.The whole sag turned into a depression stage in Miocene with little fault activity.The oil and gas exploration in the Leidong Sag should restart from the evaluation of advantageous migration system.Breakthroughs may be achieved on the uplift,southern slope,and northern steep slope.