南美东缘盐岩发育特征及其与油气聚集的关系

通过对南美东缘13个被动陆缘盆地系统解剖，总结了南美东缘盐岩发育特征：平面上盐岩主要发育在中部7个盆地中，发育薄层区、过渡区和厚层区等3种类型盐岩发育区；纵向上发育在白垩纪Aptian时期，发育时间先北后南；主要发育3种盐构造类型--整合型(非刺穿)盐构造、不整合型（刺穿）盐构造和过渡型盐构造，对应发育8种油气圈闭类型。分析了盐岩的发育对南美东缘油气富集的重要控制作用：平面上盐岩层平面展布控制油气的平面富集，中部7个盐岩发育盆地富集了整个南美东缘油气总量的95%；纵向上盐岩层将含盐盆地一分为二，形成盐上和盐下两套含油气层系，厚层盐岩区油气主要富集在盐下层系，薄层区和厚度剧烈变化区的油气则主要富集在盐上层系；岩性上倾尖灭、不整合遮挡、滚动背斜和断层遮挡型等4种盐构造相关圈闭是主要的油气成藏圈闭类型；盐构造运动形成的“盐天窗”是下部烃源岩与上部储集层沟通的主要通道；厚层盐岩层的存在为盐下油气的富集提供良好的封盖条件。

Salt Development Characteristics and Its Controlling on Hydrocarbon Accumulation in Eastern Margin of South America

Based on systematic analysis of 13 passive margin basins in South America, the authors conclude the characteristics of salt development: In plane, the salts mainly distributed in the middle 7 basins; In vertical, the salts developed at Cretaceous Aptian and migrated from north to south; There are 3 types of salt structures including unconformity type,conformity type and transitional type, 8 types of hydrocarbon traps. According to the planar distribution characteristics, the salt is formed in three mode, thin, transitional and thick mode. The development of salt controlled hydrocarbon accumulation in eastern area of South America: The plane distribution of salt controls hydrocarbon plane accumulation, the middle 7 salt developed basin accumulated more than 95% of the total hydrocarbon resource; The salt layer splits the basin into two parts in vertical, which formed post salt and pre salt sets of hydrocarbon bearing reservoir. Hydrocarbon mainly accumulated in pre-salt formation in thick salt area while in post salt layers in thin and fierce change salt area due to the development of ‘salt window’; Salt related traps are the main hydrocarbon accumulation traps; The ‘salt window’ which formed by salt movement is the main pathway to connect lower source rock and upper reservoirs; Thick salt layer provides perfect sealing condition for pre-salt hydrocarbon accumulation.