Exploration and production from formations deposited in low‐gradient fluvial systems is typically associated with a high degree of uncertainty; a reflection of the inherent characteristics of these environments, notably the dominance of non‐reservoir floodplain fines, rapid lateral facies variations and associated heterogeneities at different scales. However, for a field development to be successful it becomes crucial to know the location, geometry, dimensions and connectivity of the most permeable facies, related to the main channel and the associated proximal overbank deposits (crevasse‐splay complexes). With the aim of addressing this problem, a multi‐disciplinary study is presented, combining outcrop data, high‐resolution sedimentological descriptions and advanced visualization techniques based on Digital Outcrop Models. This is compared with subsurface data from behind the outcrop (core, gamma ray and borehole image logs). The Mudstone–Sandstone Unit of the Triassic Red Beds of Iberian Meseta formation in south‐central Spain was selected for the present study. The unit is characterized by the lateral and vertical stacking of four architectural elements: (i) channelized sandstone bodies; (ii) asymmetrical sigmoidal‐shaped sandstone bodies; (iii) lobe‐shaped to sheet‐like sandstone bodies; and (iv) sheet‐like mudstones. These elements represent meandering channel, crevasse‐channel‐splay and floodplain sub‐environments, comprising a distal, low‐gradient meandering fluvial system. Together with well‐documented outcrop and core facies, calibrated log responses are also presented for the channel bodies (bell‐shape Gamma Ray profile, random azimuths and low to high dip angles), the crevasse‐splay bodies (funnel‐shape Gamma Ray profile, unidirectional azimuths and low dip angles) and the floodplain deposits (serrated Gamma Ray profile, unidirectional azimuths and very low dip angles). The full integration of outcrop and subsurface datasets has enabled generation of a robust conceptual model with predictive potential when establishing the three‐dimensional stacking of facies, distribution of heterogeneities, and the connectivity between reservoir rock geobodies of primary (channel) and secondary (crevasse complex) interest in this type of fluvial reservoir.

中文翻译：

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漫滩砂岩的储层结构和非均质性分布：露头，岩心和电缆测井的主要特征

沉积在低梯度​​河流系统中的地层的勘探和生产通常具有高度的不确定性。反映了这些环境的固有特征，特别是非水库洪泛区细粉的优势，快速的侧相变化以及不同尺度下的相关异质性。但是，要使油田开发成功，了解与主要河道和相关的近岸上溢沉积物（裂隙-展布复合体）有关的最可渗透相的位置，几何形状，尺寸和连通性至关重要。为了解决这个问题，提出了一项多学科研究，结合了露头数据，高分辨率沉积学描述和基于数字露头模型的先进可视化技术。将其与露头后面的地下数据（岩心，伽玛射线和井眼图像测井）进行比较。本研究选择了西班牙中南部伊比利亚Meseta组三叠纪红层的泥岩-砂岩单元。该单元的特点是横向和纵向堆叠了四个建筑元素：（i）通道化砂岩体；（ii）不对称的S形砂岩体；（iii）叶状到片状砂岩体；（iv）片状泥岩。这些要素代表蜿蜒河道，裂缝通道和洪泛平原亚环境，包括远端低梯度的蜿蜒河流系统。连同有据可查的露头和岩心相一起，还给出了通道体的校准测井响应（钟形伽马射线剖面，随机方位角和低至高倾角），裂隙扩张体（漏斗形伽马射线剖面，单向方位角和低倾角）和洪泛区沉积物（锯齿状伽马射线剖面，单向方位角和极低倾角）。露头和地下数据集的完全整合，使得在建立相的三维堆积，非均质性分布以及一次（河道）和次要（裂隙复杂）储层岩石地体之间的连通性时，能够生成具有预测潜力的强大概念模型。 ）对这种河流水库的兴趣。