关键词: 层序地层分析, 裂谷盆地, 油气勘探, 烃源岩, 成藏组合类型

Abstract: Evolution of rift basins is divided into rift initiation,rift climax,immediate post-rift,and late post-rift stages.The key surfaces, which reflect the tectonic evolutionary stages, are pre-rift unconformity surface, transgressive surface, maximum flooding surface,and top unconformity surface of immediate post-rift sediments.Maximum flooding deposits are most developed intervals of possible source rocks.Mapping of the key surfaces and defining of source rocks are important for hydrocarbon exploration of rift basins.Play types of rift basins are:(1)buried-hill pools of pre-rift stage; (2)fluvial,delta,and subaqueous fan sandstone and conglomerate pools of lowstand systems tract deposited during rift initiation stage; (3)gravity flow channel sandstone and turbidite fan pools of rift-climax transgressive systems tract;and (4)fan delta,braid delta,delta and fluvial sand stone pools of immediate post-rift highstand systems tract.Play types of depression stage of faulted-depression stacked basins are incised valley,fluvial-delta,and shoreface sandstone pools.Sequence stratigraphic study of petroliferous provinces,genesis of nonmarine sequences,and high-resolution sequence stratigraphic study should be enhanced in hydrocarbon exploration practices of China in the 21st century,in order to serve for discovering new petroliferous sags and strata and finding subtle traps and new reserves in "matured" exploration regions.

Key words: sequence stratigraphic analysis, rift basins, hydrocarbon exploration, source rocks, play types