Paleofluid Flow, Fracturing and Reservoir Implications in dolostone reservoirs in foreland and intracratonic tectonic settings

尽管近二十年来对涉及白云化的成岩流体的起源进行了大量的研究，但关于白云岩形成的过程/机制的争论仍在继续，特别是关于流体流动的时间和这些流体的化学性质，以及块状白云岩在近地表环境中形成的程度，而不是在不同埋藏深度的热液和埋藏过程中形成的程度。目前的建议是一个正在进行的研究计划的一部分，从概念上和实验上，研究沉积盆地中成岩流体的化学、来源和流体流动事件的时间。它的目的是特别强调断层和裂缝的成岩作用，因为断层和裂缝往往是主要的管道，无论是被动的还是主动的成岩流体。这些流体不仅导致裂缝矿化，而且可能对寄主碳酸盐岩产生重要的成岩作用，如溶蚀、再结晶和白云石化。利用综合场、构造、岩石学和地球化学工具对流体流动进行量化，也可用于在区域盆地尺度上建立储层孔隙度和渗透率时空分布和连通性的概念模型。今后5年的研究目标是：(1)更好地量化沉积盆地主要成岩事件及其成因流体；(2)确定裂缝与变形或构造事件（即裂缝成岩作用）之间的关系；(3)流体/岩石相互作用的地球化学模拟（例如使用反应输运模型）；(4)确定古流体流动模式（如数值模拟和地球化学模拟）；(5)探讨了镁同位素和团块同位素在白云化流体源上的应用及温度—流体组成关系；(6)揭示成岩事件对孔隙演化的影响。这些目标可以通过仔细检查构造参数、绘制成岩和构造成分的区域和局部分布图、地球化学（稳定和放射性同位素测量、流体包裹体）、埋藏和热历史曲线以及定量盆地建模技术来实现。从不同地质环境（稳定的克拉通内区域与盆地内构造更活跃的区域）的碳酸盐岩储层及其露头类似物中取样，将有助于更好地理解和量化白云岩的起源、时间和空间分布，以及每种地质环境下的其他成岩阶段。对加拿大西部沉积盆地（WCSB）、密歇根盆地和中东盆地的古流体流动和成岩作用进行对比研究。

Despite considerable research over the last two decades on the origin of diagenetic fluids involving dolomitization, the debate about the process/ mechanism of dolomite formation is still is ongoing, especially regarding timing of fluid flow and chemistry of these fluids and the extent to which massive dolostones formed in near surface environments as opposed to formation at variable burial depths by hydrothermal and burial processes. The present proposal is part of an ongoing research program, both conceptually and experimentally, on the chemistry, source(s) of diagenetic fluids and timing of fluid flow events in sedimentary basins. It is aimed to put special emphasis on fault and fracture diagenesis, because faults and fractures are often the primary conduits for diagenetic fluids, whether passively or actively. These fluids do not only result in fracture mineralization but may also induce important diagenetic modifications to the host carbonate rocks, such as dissolution, recrystallization and dolomitization. Quantification of the fluid flow using integrated field, structural, petrographic and geochemical tools can be also used to develop conceptual models for the spatial and temporal distribution and connectivity of reservoir porosity and permeability on a regional basinal scale. The proposed research program for the next 5 years will have the following objectives: (1) a better quantification of the main diagenetic events and their responsible originating fluids in sedimentary basins; (2) determination of the relationship between the fractures and deformational or tectonic events (i.e. fracture diagenesis); (3) geochemical simulation of fluid/rock interaction (e.g. using reactive transport modeling); (4) determination of patterns of paleo-fluid flow (e.g. numerical and geochemical modeling); (5) investigate the application of Mg-isotopes and clumped isotopes on source(s) for dolomitizing fluids and temperature-fluid composition relationship; and, (6) unravel the impact of diagenetic events porosity evolution. These objectives can be achieved through careful examination of textural parameters, mapping of regional and local distribution of diagenetic and structural components, geochemistry (stable and radiogenic isotope measurements, fluid inclusions), burial and thermal history curves and quantitative basin modeling techniques. Sampling from carbonate reservoirs and their outcrop analogs from different geologic settings (stable intracratonic areas vs. tectonically more active areas within the basin) will allow a better understanding and quantification of the origin, timing and spatial distribution of dolomites and other diagenetic phases within each setting. Comparative studies on paleo-fluid flow and diagenesis will also be carried out between the Western Canada Sedimentary Basin (WCSB), Michigan Basin and Middle East basins.