Understanding the depositional setting of siliciclastics reservoir is fundamental process to exploration and development of hydrocarbon reservoirs and to the multi-phase cycle of the oil and gas industry. Typically, core samples from existing or potential reservoirs can be used for interpretation of depositional environment. However, the lack of core samples in certain reservoirs represents a challenge for reservoir development plans and further exploration. To overcome the absence of core samples in the middle Miocene Sidri Member in the Badri field, Gulf of Suez, this study aimed to reconstruct its depositional settings by coupling well logging patterns and petrographic characterization of ditch cuttings. Consequently, 30 thin section samples representing the reservoir section of four wells were described in detail and standard petrographic characteristics were determined. Then, gamma-ray (GR) log patterns of the studied reservoir wells were used for interpretation of depositional environment. Petrographic analysis indicates that the sandstone reservoir is fine- to medium-grained arkose with dominant siliceous cement and composed mainly of quartz, feldspars, and lithic fragments. Pores reflecting primary and secondary porosity as well as inter-granular pores are dominant. The facies analysis indicates that the studied member has a heterogeneous nature and rapid facies change; its main lithofacies are blocky sandstones, intercalated sandstones and shales, and shales. Three electrofacies were interpreted in the studied section: (1) electrofacies-A (blocky sandstones), which is characterized by a cylindrical-shaped (right boxcar) GR trend; (2) electrofacies-B (intercalated sandstones and shales), which is characterized by an irregular log trend with serrated shape; and (3) electrofacies-C (shales), which is characterized by irregular GR trend and has no character. The interpreted results indicate a tidal channel depositional setting for electrofacies-A, mixed tidal flat depositional setting for electrofacies-B, and low relief offshore mudstone depositional setting for electrofacies-C. Finally, the results illustrate how the coupling of GR patterns with the analysis of petrographic characteristics can be used to understand the depositional setting of a hydrocarbon reservoir that lacks core samples. This work could be useful for assessment of reservoir distribution and quality, for reduction of uncertainty during field development, as well as for providing useful insight to similar hydrocarbon reservoirs elsewhere.

了解硅质碎屑岩储层的沉积环境是油气藏勘探开发和油气工业多阶段循环的基本过程。通常，来自现有或潜在储层的岩心样本可用于解释沉积环境。但是，某些储层中缺乏岩心样品，这对储层开发计划和进一步勘探构成了挑战。为了克服苏伊士湾Badri油田中新世Sidri中段缺少岩心样品的情况，本研究旨在通过结合测井模式和沟cutting岩的岩石学特征来重建其沉积环境。所以，详细描述了代表四个井的储层的30个薄片样品，并确定了标准岩石学特征。然后，将研究井的伽马射线（GR）测井模式用于解释沉积环境。岩石学分析表明，砂岩储层为细粒至中粒的黑糖，含优势硅质胶结物，主要由石英，长石和岩屑组成。反映主要和次要孔隙度以及粒间孔隙的孔隙占主导。相分析表明，研究对象具有非均质的性质和快速的相变。其主要岩相为块状砂岩，插层砂岩和页岩以及页岩。研究部分解释了三种电相：（1）电相-A（块状砂岩），其特征是圆柱形（右棚车）GR趋势；（2）电相-B（夹层砂岩和页岩），其特征是不规则的对数趋势，呈锯齿状；（3）电相-C（页岩），其特征为不规则的GR趋势，无特征。解释的结果表明，电相-A的潮汐河道沉积环境，电相-B的混合潮汐平面沉积环境和电相-C的低浮力海上泥岩沉积环境。最后，结果说明了如何将GR模式与岩石学特征分析相结合，以了解缺乏岩心样品的油气藏的沉积环境。