Comparison of Subsalt Hydrocarbon Accumulation Characteristics in Basins on Both Sides of the Mid-South Atlantic

The basins on both sides of the middle of South Atlantic are the conjugate passive continental margin basins, which formed in the Atlantic Ocean rift period. They have the similar evolution and hydrocarbon accumulation characteristics, while the exploration degree and exploration area are quite different. The current exploration and research in this region focus on how to draw lessons from the pre-salt oil and gas exploration in Brazil Santos Basin and Campos Basin of the South America, and guide the pre-salt oil and gas exploration in Angola Kuanza Basin in West Africa. In this study, we carried out contrast analysis of the oil and gas distribution characteristics, tectonic sedimentary characteristics and hydrocarbon accumulation conditions between the basins on the both sides of South Atlantic, and pointed out the similarities and differences of hydrocarbon accumulation characteristics. The study shows that Kuanza Basin in West Africa and Campos Basin in Brazil have horst-graben structure pattern similar to basement structure. In a specific paleo-water depth area during the deposition of subsalt reservoirs, paleo-shallow water area far from provenance area formed by basement uplift, meanwhile carbonate reservoir and related structural traps developed. Besides, hydrocarbon was supplied from surrounding graben area, with good sealing conditions provided by salt rock. And that can offer good conditions for the formation and enrichment of oil and gas under salt, which will become a new growth point for Angola's reserves in the future.