关键词: 下刚果盆地, 深水区, 油气成藏要素, 成藏模式

Abstract: Lower Congo Basin is one of the hydrocarbon abundant margin basins of West Africa passive continent. With a large number of oil and gas discoveries made particularly in the deepwater zone, the area has become the hot spot for oil and gas exploration. The characteristics of hydrocarbon accumulations in the deepwater zone of the basin are very complicated. Two sets of source rock developed in the area: pre-salt marine and post-salt lacustrine source rock. There are three sets of favorable reservoir-caprock assemblages-deep layer, middle layer and shallow layer. The current exploration has confirmed that the upper Neogene turbidite sandstone and deep Albian carbonate rock reservoirs are the two main targets. Comparatively speaking, the physical properties of reservoirs are good with a desirable matching relation between reservoir and cap-rock. The middle and shallow layer assemblages are mainly the structural-lithological traps while the deep layer assemblage is mainly the near S-N and salt rock-related structural traps. All the elements of the reservoirs are well matched in terms of time and space. Based on the study of the reservoir elements, three favorable accumulations models are established for the post-salt marine source rock and Neogene turbidite sandstone reservoirs, post-salt marine source rock, and Lower Cretaceous carbonate rock reservoirs and pre-salt lacustrine source rock and Lower Cretaceous carbonate rock reservoirs in the deepwater zone of Lower Congo Basin