Abstract The development of shale oil/gas reservoirs has suffered constant changes, innovations and successive reactions, although it depends on the success of hydraulic fracturing, and mineralogy and morphology play a very important role in establishing brittleness and therefore controlling it. In this study, mineralogical and morphological characteristics of the Cretaceous Galembo Member Mudstones of the La Luna Formation in the Middle Magdalena Valley Basin (Colombia) have been characterized using scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy to obtain information on mineral morphology, size, microfabric, microtexture, and elemental composition. The analyzed rocks can be classified in several lithofacies: Nonlaminated to slight laminated foraminifera wackestones, Moderate to well-laminated highly fossiliferous and organic-rich mudstones, Fossiliferous carbonate concretions, Nonlaminated siliceous and fossiliferous claystones, and Nonlaminated calcareous mudstones. In general, these rocks show fossil content typical from a predominantly deep marine paleoenvironmental conditions, although minor changes can generate variations in the relative proportion of terrigenous material, precipitation of organic matter and diagenetic alterations. They consist of calcite, mainly cryptocrystalline micrite, microcrystalline quartz, illite and kaolinite, with minor phosphates (apatite), sulfides (framboidal pyrite and sphalerite) and sulfates (barite). Porosity in the analyzed rocks can be found into matrix pores (interparticle pores between mineral particles and intraparticle pores within mineral particles) and microfractures.

中文翻译：

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中马格达莱纳河谷盆地（哥伦比亚）La Luna 组白垩纪 Galembo 段泥岩的矿物学和形态学特征

摘要 页岩油气藏的开发虽然有赖于水力压裂的成功与否，但不断发生变化、创新和接续反应，而矿物学和形态对脆性的形成和控制起着非常重要的作用。在这项研究中，使用扫描电子显微镜结合能量色散 X 射线光谱仪对中马格达莱纳河谷盆地（哥伦比亚）La Luna 组白垩纪 Galembo 段泥岩的矿物学和形态特征进行了表征，以获得矿物形态信息、尺寸、微织物、微纹理和元素组成。所分析的岩石可分为几种岩相： 非层状到轻微层状有孔虫的碎屑岩，中等至良好层状的高度含化石和富含有机质的泥岩、含化石碳酸盐结核、非层状硅质和含化石粘土岩以及非层状钙质泥岩。一般而言，这些岩石显示出主要来自深海古环境条件的典型化石含量，尽管微小的变化会导致陆源物质、有机物质沉淀和成岩改变的相对比例发生变化。它们由方解石组成，主要是隐晶泥晶、微晶石英、伊利石和高岭石，还有少量的磷酸盐（磷灰石）、硫化物（菱形黄铁矿和闪锌矿）和硫酸盐（重晶石）。