Quartz is one of the most common minerals in the Earth's crust, and its deposition and cycling are ubiquitous and crucial in energy and environmental sciences. Due to the existence of multiple types of quartz and diverse mechanisms that result in their formation, this variation is expected to significantly impact shale deposition, diagenesis, and reservoir properties. Moreover, it plays a crucial role in the enrichment, development, and production of shale oil and gas plays. Considering their importance, this study systematically summarizes observation and various research methods, such as optical and scanning electron microscopy (SEM), cathodoluminescence (CL), energy dispersive spectrometry (EDS), X-ray fluorescence (XRF), quantitative evaluation of minerals by scanning electron microscopy (QEMSCAN), fluid inclusion, which supports our understanding of the mineral diagenesis and generation of both detrital and authigenic origins. Parent rock type, transport distance, and depositional environment are known factors that control the grain size, sorting, roundness and types of detrital quartz. The authigenic quartz contains biogenic, hydrothermal origins and clay mineral transformation while fluid source, diagenetic mechanisms, and growth space control the formation time and crystal size of them. In addition, quartz controls the total organic carbon content, reservoir quality, fracturing ability, organic matter preservation and reservoir enrichment, etc. Notably, the microquartz cement derived from biosiliceous allochems (namely biogenic quartz) has a noticeable positive correlation with total organic carbon content and is formed during the early diagenetic stages which together with the detrital quartz form a rigid framework favorable to primary pores, ultimately forming high-quality marine shale reservoirs. Furthermore, the diagenesis of biogenic quartz also enhances the mechanical properties and fracturing potential of shale reservoirs. The biogenic quartz content and the thickness of shale intervals determine the potential and development of marine shale oil/gas reservoirs. However, in transitional and lacustrine shales, quartz is predominantly detrital in origin and negatively correlated with organic carbon content. In these two types of shales, detrital quartz and quartz formed during the transformation of clay minerals are known to play a positive role in the formation of shale reservoirs and hydrocarbon enrichment. Considering all of these factors, this study investigates different types and contents of quartz in typical shale oil and gas reservoirs worldwide and explains how they have influenced shale oil and gas enrichment and reservoir productivity.

中文翻译：

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石英类型、形成机制及其对页岩油气富集的影响


石英是地壳中最常见的矿物之一，它的沉积和循环无处不在，在能源和环境科学中至关重要。由于存在多种类型的石英以及导致其形成的不同机制，预计这种变化将显着影响页岩沉积、成岩作用和储层特性。此外，它在页岩油气田的富集、开发和生产中起着至关重要的作用。考虑到它们的重要性，本研究系统地总结了观察和各种研究方法，如光学和扫描电子显微镜 （SEM）、阴极发光 （CL）、能量色散光谱 （EDS）、X 射线荧光 （XRF）、扫描电子显微镜对矿物的定量评估 （QEMSCAN）、流体包裹体，这支持了我们对矿物成岩作用和碎屑和自生起源的产生的理解。母岩类型、运输距离和沉积环境是控制碎屑石英粒度、分选、圆度和类型的已知因素。自生石英包含生物成因、热液成因和粘土矿物转化，而流体来源、成岩机制和生长空间控制着它们的形成时间和晶体尺寸。此外，石英控制总有机碳含量、储层质量、压裂能力、有机质保存和储层富集等。 值得注意的是，来自生物硅质 allochem 的微石英胶结物（即生物石英）与总有机碳含量呈明显的正相关，形成于早期成岩阶段，与碎屑石英一起形成有利于原生孔隙的刚性框架，最终形成高质量的海相页岩储层。此外，生物石英的成岩作用还增强了页岩储层的机械性能和压裂潜力。生物石英含量和页岩层段厚度决定了海洋页岩油/气藏的潜力和开发。然而，在过渡页岩和湖相页岩中，石英主要由碎屑组成，与有机碳含量呈负相关。在这两种类型的页岩中，已知碎屑石英和粘土矿物转化过程中形成的石英对页岩储层的形成和碳氢化合物富集起着积极作用。考虑到所有这些因素，本研究调查了全球典型页岩油气藏中不同类型和含量的石英，并解释了它们如何影响页岩油气富集和储层生产力。