摘要
为了揭示巴西桑托斯盆地油气富集规律,指导下一步的油气勘探,结合地震、钻井等基础资料对该盆地油气成藏特征进行了综合分析,结果表明:1裂谷期湖相泥岩是盆地一套优质并广泛分布的主力烃源岩,成熟度整体呈现"东部成熟、西部过熟"的分带特征;2盐下湖相碳酸盐岩层系是盆地主要勘探领域,其中湖相微生物礁藻叠层石灰岩与生屑滩贝壳灰岩是主要的储层类型;3盐岩盖层发育四类构造样式并呈三带展布,从封盖作用上可以划分为西部薄盐-无盐通道区和东部厚盐封闭区;4盆地发育盐下、盐上两大勘探层系,其中盐下勘探层系主要位于东部厚盐封闭区,为盐下生盐下储成藏模式,而盐上勘探层系主要位于西部薄盐-无盐通道区,为盐下生盐上储成藏模式。综合分析认为,盐岩盖层厚度与烃源岩成熟度是该盆地油气成藏主控因素,具体表现为盐岩盖层厚度差异决定油气的成藏层系,而烃源岩成熟度差异决定油气藏类型;东部隆起带外带与中央坳陷带东部的盐下裂谷期勘探层系潜力较大,是未来勘探的2个有利区带。
To reveal the hydrocarbon enrichment regulations and guide the further exploration in Santos basin, the characteristics of hydrocarbon accumulation are analyzed comprehensively based on seismic, drilling and other basic data. The results show that：①the wide distributed lacustrine mudstonBe and shale in the rift stage are the main source rocks with high quality, in which the eastern part of the basin has matured source rocks and the western part has over-matured ones.②major exploration domains are pre-salt lacustrine carbonate rocks, especially the microbialites of microbial-reef and coquina of shell bank reservoirs.③four types of structural styles showing three zones distribution develop in the salt cap layers. The basin can be divided into western passage area with thin or no salt layers and eastern closed area with thick salt layers.④post-salt and pre-salt sequences are both exploration domains. Pre-salt exploration strata is mainly located in the eastern closed area with thick salt layers where the accumulation model is pre-salt source rocks and pre-salt reservoirs, and the post-salt exploration strata is mainly located in the western passage area with thin or no salt layers where the accumulation model is pre-salt source rocks and post-salt reservoirs. Analysis shows that the thickness of salt layers and the maturity of source rocks are the two factors controlling the accumulation in Santos basin. The thickness of salt layers determines the sequence of accumulation, and the maturity of source rocks defines the type of accumulation. The pre-salt sequences of rift phase in eastern uplift zone and eastern part of central depression zone have high potential and would be two favorable exploration areas.
出处
《中国海上油气》
CAS
CSCD
北大核心
2016年第4期1-8,共8页
China Offshore Oil and Gas
基金
"十二五"国家科技重大专项"大陆边缘盆地类比与油气成藏规律研究(编号:2011ZX05030-001)"部分研究成果
关键词
桑托斯盆地
成藏特征
主控因素
盐岩盖层厚度
烃源岩成熟度
勘探潜力区带
Santos basin
hydrocarbon accumulation characteristics
main control factors
salt cap thick-ness
source rock maturity
favorable exploration areas
