下刚果盆地油气成藏主控因素及勘探方向

Main factors controlling hydrocarbon accumulation and exploration orientation in Lower Congo Basin

下刚果盆地油气成藏条件非常有利,尤其盆地内沉积了阿普第阶盐岩层,发育多种类型盐相关构造,形成多种类型圈闭,同时盐岩层又是非常好的盖层。但该套盐岩层的存在也使下刚果盆地盐下、盐上油气成藏条件产生较大差异:盐下地层油气成藏的主控因素为伸展构造有关的圈闭,未来重点勘探仍以寻找伸展构造有关的油气藏类型为主要方向;盐上白垩系油气成藏的主控因素为圈闭和储层,未来勘探应以寻找与阿尔布阶Pinda组碳酸盐岩和Vermelha组的滨岸砂岩为储层并与盐构造相关的油气藏为重点;第三系油气成藏的主控因素则为烃源岩成熟度、圈闭及浊积砂体的发育,未来重点勘探方向为寻找深水—超深水区盐构造与浊积砂体复合型油气藏。

Lower Congo Basin is one of the most important petroliferous basins in West Africa and has very favorable oil-forming conditions. The halokinetics of Aptian salt in Lower Congo Basin had developed multiple types of salt-related structures and traps. The salt rock is also a very good seal. However,the existence of the salt rock caused a big difference in the conditions of hydrocarbon accumulation between sub-and supra-salt regimes. Underneath the salt,the main factor controlling hydrocarbon accumulation is the traps related to extensional structure; the orientation for its future exploration still focuses on seeking for oil and gas reservoirs related to extensional tectonics. Above the salt,the main factors controlling hydrocarbon accumulation in the Cretaceous are traps and reservoirs; the orientation for its future exploration is the search for Albian carbonate (Pinda) and Vermelha sandstone reservoirs and those related to salt tectonics. The main factors controlling Tertiary hydrocarbon accumulation are the maturity of source rock,the traps,and the turbidite sand body; the orientation for its future exploration is the search for hybrid reservoirs of salt tectonics and turbidity sandstone in deep-ultra deep water.