Northeastern Egypt is one of the most important exposures in the Middle East and North Africa to study Jurassic facies. The present study analyzes 130 thin sections from a subsurface well (Well X) in the northern Gulf of Suez, and from two surface sections at Gebel Maghara (north Sinai) and Khashm Elgalala (North Eastern Desert), Egypt for petrographic and lithofacies analyses. In the present study, detailed petrographic analysis is used as a tool to better understand the diagenetic history of the Early to Late Jurassic siliciclastic sediments; the identified diagenetic elements are inferred concerning the reservoir quality. For this, sidewall cores, scanning electron microscopy and thin sections are used to detail detrital and authigenic mineralogy; these are then used to infer the depositional framework, factors controlling reservoir characteristics, and the operating diagenetic processes. The inferred depositional paleoenvironment is a prograding and retrograding linear siliciclastic shoreline within a shallow marine carbonate platform with coal swamps and occasional cross-cutting rivers. Diagenesis, petrographical characteristics and depositional conditions are the main factors controlling continental and marine reservoir architecture. The diagenetic processes affecting siliciclastic sedimentation are near the surface, shallow to intermediate burial, and deep burial cycles with different pore fluid filling at each stage. The siliciclastic sediments have been categorized into seven depositional lithofacies - calcareous claystone (S1a), carbonaceous claystone (S1b), siltstone (S2), planar and trough cross-bedded sandstone (S3), coarse, well rounded, large scale trough cross-bedded sandstone (S4), ooid sandstone (S5) and coal (C). Grain compaction, various phases of syntaxial quartz overgrowth, carbonate cementation and replacement, creation of dissolution porosity, and clay authigenesis are the most important diagenetic processes that have affected the siliciclastic continental and marine sediments. Many different diagenetic events, both destructive and constructive, have modified porosity. The destructive events include compaction and cementation (of silica, kaolinite, ferroan dolomite, Illite, and anhydride). The constructive events include silica cementation, feldspar dissolution, and ferroan dolomite dissolution. Additionally, present data also suggest that the continental sandstones have excellent reservoir quality whereas the marine sandstones have good to very good reservoir potential. Despite the excellent reservoir quality of the continental sandstone lithofacies, the effective stratigraphic seal is leaking. The interbedded calcareous and carbonaceous claystone lithofacies may provide an excellent stratigraphic seal for these siliciclastic reservoirs. Based on these analyses, a model is proposed that can be used as a template for subsurface Jurassic reservoir characterization and reservoir discrimination.

埃及东北部是中东和北非研究侏罗纪相的最重要的机会之一。本研究分析了苏伊士湾北部的一口地下井（X井）以及埃及的Gebel Maghara（北西奈）和Khashm Elgalala（东北沙漠）的两个地表断层的130个薄层，以进行岩相学和岩相分析。在本研究中，详细的岩石学分析被用作更好地了解早，晚侏罗世硅质碎屑沉积岩成岩史的工具。推断出与储层质量有关的成岩元素。为此，使用侧壁岩心，扫描电子显微镜和薄切片来详细描述碎屑和自生矿物学。然后这些被用来推断沉积框架，控制储层特征和成岩过程的因素。推断的沉积古环境是在浅海碳酸盐岩台地中线性的硅质碎屑岩海岸线的渐进和逆行，该大陆碳酸盐沼泽地带有煤田和偶尔穿过的河流。成岩作用，岩石学特征和沉积条件是控制大陆和海洋储层构造的主要因素。影响硅质碎屑沉积的成岩过程是在地表附近，从浅埋到中等埋藏，以及深埋藏循环，每个阶段的孔隙流体充满程度不同。硅质碎屑沉积物分为7个沉积岩相-钙质黏土（S1a），碳质黏土（S1b），粉砂岩（S2），平面和槽形交叉层砂岩（S3），圆形的大型槽状交叉层砂岩（S4），卵形砂岩（S5）和煤（C）。晶粒致密化，语法石英过度生长的各个阶段，碳酸盐胶结作用和置换，溶解孔隙的产生以及粘土的成岩作用是影响硅质碎屑大陆和海洋沉积物的最重要的成岩过程。许多不同的成岩作用，包括破坏性的和建设性的，都改变了孔隙度。破坏性事件包括压实和胶结（二氧化硅，高岭石，亚铁白云石，伊利石和酸酐）。建设性事件包括二氧化硅胶结，长石溶解和亚铁白云岩溶解。另外，目前的数据还表明，大陆砂岩具有优良的储层质量，而海相砂岩具有良好至非常好的储层潜力。尽管大陆砂岩岩相具有出色的储层质量，但有效的地层密封仍在泄漏。夹层的钙质和碳质粘土岩岩相可为这些硅质碎屑岩储层提供极好的地层封闭性。基于这些分析，提出了一个模型，该模型可以用作侏罗纪地下储层表征和储层识别的模板。夹层的钙质和碳质粘土岩岩相可为这些硅质碎屑岩储层提供极好的地层封闭性。基于这些分析，提出了一个模型，该模型可以用作侏罗纪地下储层表征和储层识别的模板。夹层的钙质和碳质粘土岩岩相可为这些硅质碎屑岩储层提供极好的地层封闭性。基于这些分析，提出了一个模型，该模型可以用作侏罗纪地下储层表征和储层识别的模板。