摘要:
据IHS全球能源数据库(2010)统计,坎普斯—桑托斯盆地贡献了巴西83%的油气储量和62%的油气产量。坎普斯—桑托斯盆地位于巴西东南部沿海,属于中生界裂谷盆地基础上叠合形成的大西洋型被动大陆边缘盆地。两盆地地理位置相邻,具有相似的构造演化历史和油气地质条件,但油气富集规律呈明显的差异。其中,坎普斯盆地油气主要富集于上白垩—中新统浊积砂岩储层,以重油为主;桑托斯盆地油气主要富集于下白垩统碳酸盐岩储层,以中质油、轻质油和天然气为主。通过对盆地基底结构、油气田分布、流体性质、成藏要素和成藏组合差异分析,认为盐岩是区域油气出现差异富集的主要原因,基底结构和漂移期沉积地层发育则控制了盆地盐岩形变和分布。
Abstract:
The Campos and Santos basins are considered as the most important oil industrial base of Brazil. The two basins as a whole are one of the four major regions around the world rich in deepwater hydrocarbon. According to the statistics by the IHS Global Energy database (2010), The Campos and Santos basins contributed 83% of the oil and gas reserves and 62% of the oil and gas production in Brazil. The two basins are located along the southeast coast of Brazil, both belonging to Atlantic-type passive marginal basins superimposed on the Mesozoic rift basins. They are next to each other, have experienced similar tectonic evolutionary history and under similar petroleum geological conditions. However, the hydrocarbon accumulation pattern of the two basins are obviously different. In the Campos Basin, oil and gas primarily accumulated in the Upper Cretaceous-Miocene turbidite sandstone reservoirs characterized by heavy crude oil, while in the Santos Basin, hydrocarbon is mainly found in the Lower Cretaceous carbonate reservoir characterized by intermediate oil, light oil and natural gas. We made careful study on the two basins in this paper with special attention to the difference of basement structure, oil and gas fields distribution pattern, fluid properties, accumulation elements and plays. Our results show that spatial differentiation of oil and gas distribution owes its origin to salt layer. And the basement structure and sedimentary sequence formed in the drifting period contributed a lot to the deformation and distribution of salt layer.
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