Diagenetic models for silt-rich mudstone (siltstone) are less advanced than those for sandstone and clay-rich mudstone. In addition, the influences of diagenetic processes on reservoir quality in siltstone formations are poorly understood. Here we examine the roles of depositional facies, detrital composition, and diagenetic processes in the compositional evolution and reservoir quality of the Lower Triassic Montney Formation, a prominent siltstone-dominated reservoir in western Canada with very large reserves of oil, gas-liquids and natural gas. We applied advanced, high-resolution petrographic methods including SEM (SE, BSE, EDX and SEM-CL), XRD, and QEMSCAN technologies, as well as He-pycnometry on samples from 17 different locations within the basin that represent a range of depths and thermal maturities. Cross-cutting and overgrowth relationships and volumes of authigenic phases demonstrate massive precipitation of quartz, feldspar, dolomite, calcite and anhydrite cements at shallow burial depths, leading to compositional homogeneity among different lithofacies. We propose that the precipitation of large volumes of cement resulted from high fluid flux through the formation at shallow depth, possibly driven by reflux of concentrated seawater in nearshore saltpans. Siltstones preserve relatively high porosity and permeability at shallow burial depths, differing from clay-rich mudstones. In contrast to sandstones, deep burial diagenesis played a relatively minor role in the compositional evolution of the Montney Formation siltstone and is expressed in the form of pressure solution and minor amounts of fibrous illite precipitation.

富粉质泥岩（粉砂岩）的成岩模型不如砂岩和富粘土泥岩的成岩模型先进。此外，成岩过程对粉砂岩地层储层质量的影响了解得很少。在这里，我们研究了沉积相，碎屑成分和成岩作用在下三叠系蒙尼组的演化和储层质量中的作用，该组是加拿大西部以粉砂岩为主的重要储层，具有大量的石油，气液和天然储量。气体。我们对盆地中17个不同位置的样品应用了包括SEM（SE，BSE，EDX和SEM-CL），XRD和QEMSCAN技术在内的先进高分辨率岩相学方法，以及氦比重法和热成熟度。横切和过度生长的关系以及自生相的体积表明，浅埋深的石英，长石，白云石，方解石和硬石膏的大量沉淀，导致不同岩相之间的成分均一。我们认为，大量水泥的沉淀是由于在浅层深处流过地层的流体通量较高而引起的，这可能是由于浓盐水在近海盐田中的回流所致。粉砂岩在浅埋深度保留了较高的孔隙度和渗透率，与富含粘土的泥岩不同。与砂岩相比，深埋成岩作用在蒙尼组粉砂岩的成分演化中起相对较小的作用，并以压力溶液和少量伊利石纤维沉淀的形式表达。