南大西洋含盐盆地油气富集规律及勘探潜力

南大西洋含盐盆地油气资源丰富，各盆地具有相同的构造演化历史和相似的地层发育特征，但油气分布极不均衡。研究了这些盆地构造演化、地层、油气成藏条件及油气分布特征后指出，南大西洋盆地经历了裂谷、过渡和被动大陆边缘3个演化阶段，发育盐下、盐岩和盐上3套层序，盐下、盐上2套烃源岩，盐下、盐上碳酸盐岩和盐上碎屑岩3套储集层，形成3套成藏组合。盐上成藏组合油气富集主要取决于盐上浊积砂岩储集层的发育程度和盐上烃源岩的成熟度，在下刚果—刚果扇盆地最为富集；盐下-盐上成藏组合油气富集主要取决于油气运移通道、盐上储集层的发育程度，在坎波斯盆地最为富集；盐下成藏组合油气富集主要取决于裂谷盆地规模、基底隆起和盐岩盖层，在桑托斯盆地最为富集。宽扎盆地的盐下层系、桑托斯盆地和坎波斯盆地的外部高地带和中部低凸带盐下碳酸盐岩、各盐盆伸展区盐上碳酸盐岩层系是极具勘探潜力的新领域。

Hydrocarbon Enrichment Characteristics and Exploration Potentials in Salt Basins of South Atlantic

The salt basins in the South Atlantic are characterized by rich hydrocarbon resources, same tectonic evolution history and similar stratigraphic features as well as very uneven distribution of oil and gas. This paper suggested from studies of the tectonic evolutions, strata, hydrocarbon accumulation conditions and petroleum distribution characteristics that these basins had experienced three evolution stages of rifting, transition and passive continental margin, with corresponding development of pre-salt, salt and post-salt sequences. And the pre-salt and post-salt source rocks, pre-salt and post-salt carbonate rocks and post-salt clastic rocks as reservoir rocks formed three sets of hydrocarbon accumulation combinations. The development of post-salt turbidite sand reservoir and the maturity of post-salt source rocks controlled the hydrocarbon enrichment of the post-salt combination, which is found in Lower Congo-Congo Fan basin; the oil-gas migration channels and the development of post-salt reservoir rocks controlled the hydrocarbon enrichment of the pre-salt to post-salt combination, which appears in Campos basin; and the rift basin scale, basement uplift and salt cap rock controlled the pre-salt combination, which occurs in Santos basin. Hence, the Kwanza basin’s pre-salt sequence, the Santos basin’s and the Campos basin’s pre-salt carbonate rocks in their outside high-swell zones and middle low-swell zones as well as the post-salt carbonate rock sequences in extending areas of each salt basin are all new domains with great exploration potentials