Abstract The Espirito Santo Basin, one of the Brazilian marginal basins formed during the Gondwana break-up, is composed by three main depositional units – rift, sag and drift phases. The Mucuri Member sandstones are the Aptian sag phase related, onshore reservoirs deposited at the margins of the lacustrine system were the pre-salt (pre-evaporitic succession) lacustrine carbonate reservoirs were generated. The main objective of this article focuses on the stratigraphic and sedimentological definition of depositional model from the top of the Mucuri Member, in the transition to Itaunas Member evaporites of Mariricu Formation, since the depositional conditions of this interval until date remain under discussions and can contribute to the understanding of the correlated pre-salt reservoirs. Core description in detailed scale (1:50) associated with gamma-ray logs allowed the identification of nineteen facies, grouped into five facies associations: gravelly fluvial channel, poorly confined fluvial channels, upper shoreface, lower shoreface and offshore. Stacking patterns of facies associations allowed the definition of four cycles: T, T-R, normal R and forced R cycles. Although these cycles are easily recognizable in the cores, their correlation between wells was not possible. Geochemical analyses of 87Sr/86Sr ratio from anhydrites layers interbedded with the Mucuri sandstones confirmed a non-marine composition for the precipitating fluids. The integrated evidence suggests a wave dominated lacustrine coastal environment for the subaqueous Mucuri Member deposits.

中文翻译：

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波控湖缘，Aptian 盐下，Mucuri 段，Espírito Santo 盆地

摘要 Espirito Santo 盆地是冈瓦纳大陆断裂形成的巴西边缘盆地之一，由三个主要沉积单元组成——裂谷相、凹陷相和漂移相。Mucuri 段砂岩是与 Aptian 凹陷相相关的，沉积在湖相系统边缘的陆上储层是盐下（蒸发前序列）湖相碳酸盐岩储层的产生。本文的主要目的集中在从 Mucuri 段顶部到 Mariricu 组的 Itaunas 段蒸发岩过渡期间沉积模型的地层学和沉积学定义，因为该层段的沉积条件至今仍在讨论中，可以做出贡献对相关盐下储层的了解。详细比例的核心描述（1：50) 与伽马射线测井相关联，可以识别 19 个相，分为五个相协会：砾石河流通道、封闭性较差的河流通道、上岸面、下岸面和近海。相关联的堆叠模式允许定义四个循环：T、TR、正常 R 和强制 R 循环。尽管这些循环在岩心中很容易识别，但它们在井之间的相关性是不可能的。对夹在 Mucuri 砂岩中的硬石膏层的 87Sr/86Sr 比率的地球化学分析证实了沉淀流体的非海洋成分。综合证据表明，水下穆库里段沉积物的湖相沿海环境以波浪为主。砾石河道、密闭性较差的河道、上岸面、下岸面和近海。相关联的堆叠模式允许定义四个循环：T、TR、正常 R 和强制 R 循环。尽管这些循环在岩心中很容易识别，但它们在井之间的相关性是不可能的。对夹在 Mucuri 砂岩中的硬石膏层的 87Sr/86Sr 比率的地球化学分析证实了沉淀流体的非海洋成分。综合证据表明，水下穆库里段沉积物的湖相沿海环境以波浪为主。砾石河道、密闭性较差的河道、上岸面、下岸面和近海。相关联的堆叠模式允许定义四个循环：T、TR、正常 R 和强制 R 循环。尽管这些循环在岩心中很容易识别，但它们在井之间的相关性是不可能的。对夹在 Mucuri 砂岩中的硬石膏层的 87Sr/86Sr 比率的地球化学分析证实了沉淀流体的非海洋成分。综合证据表明，水下穆库里段沉积物的湖相沿海环境以波浪为主。尽管这些循环在岩心中很容易识别，但它们在井之间的相关性是不可能的。对夹在 Mucuri 砂岩中的硬石膏层的 87Sr/86Sr 比率的地球化学分析证实了沉淀流体的非海洋成分。综合证据表明，水下穆库里段沉积物的湖相沿海环境以波浪为主。尽管这些循环在岩心中很容易识别，但它们在井之间的相关性是不可能的。对夹在 Mucuri 砂岩中的硬石膏层的 87Sr/86Sr 比率的地球化学分析证实了沉淀流体的非海洋成分。综合证据表明，水下穆库里段沉积物的湖相沿海环境以波浪为主。