Modeling and Epistemic Uncertainty Analysis of Faults as Conduit-Barriers to Fluid Flow and Salinization in Siliciclastic Aquifer Systems

断层在沉积盆地中作为流体流动的通道和屏障的作用引起了广泛的兴趣。人们的兴趣很大程度上来自于试图了解断层在碳氢化合物迁移和封存中的作用、封存过程中二氧化碳的泄漏以及作为浅层含水层系统和深层含水层系统中流动的管道和屏障的作用。盆地环境。该项目将在对认识不确定性进行严格分析的情况下，研究一个断层作为硅质含水层系统中流体流动和地下水盐碱化的屏障。路易斯安那州的巴吞鲁日断层为研究和测试各向异性断层渗透率的概念提供了理想的野外区域，因为该区域存在大量的历史和野外数据。此外，断层在断层以北的一个主要市政和工业淡水来源的盐碱化中所起的作用还不完全清楚。该项目将测试四个假设：（1）可以使用Bense和Person（2006年）断层渗透率方法来描述断层的水力特性，（2）可以确定深层盐水含水层沿断层面向上的垂直渗漏或跨断层的侧向渗漏是否是盐碱化的主要原因，（3）贝叶斯模型平均（BMA）是一种有效的方法，可以量化模型参数和模型结构中各种认知不确定性来源下的盐度预测不确定性;（4）所提出的实验设计是减少盐渍化预测中认知不确定性的有效方法。该项目的成果将显着增加的有效性，以减少认识的不确定性，在盐渍化模型的BMA为基础的实验设计的理解。该项目还将提高对硅质含水层系统中地下水盐碱化的巴吞鲁日断层的认识。 该项目提供了一种手段，用于表征硅质岩序列中断层的渗透性，并开发技术，用于量化和减少流体流动和污染物跨断层和沿着断层运输的建模中的不确定性。BMA分析将推进对此类研究中不确定性来源的研究。特别是，该项目将显着推进技术在流体流动和南部丘陵含水层系统的盐碱化的数值模拟和不确定性分析，并将提供该地区的地下地质，水文地质和水文地球化学的详细知识。南部山区含水层系统的盐水入侵目前是路易斯安那州政府、当地水务公司和工业界的一个紧迫问题。含水层系统目前提供高质量的地下水，供四个行政区的公民使用，但由于引入盐水沃茨，该系统面临受到损害的危险。该项目的结果将有助于指导未来的盐碱化建模和修复工作，无论是在巴吞鲁日地区和其他类似的断层和松散的硅质含水层系统。拟议研究对整个社会的一个非常实际的好处是更好地了解盐碱化的过程和速率，并开发大巴吞鲁日地区南山含水层系统的修复方法。

There has been extensive interest in the role of faults as conduits and barriers to fluid flow in sedimentary basins. Much of the interest has been generated by the attempt to understand the role of faults in the migration and entrapment of hydrocarbons, the leakage of carbon dioxide during sequestration, and as conduits and barriers to flow in both shallow aquifer systems and in deep basinal settings. The project will study a fault as a conduit-barrier to fluid flow and groundwater salinization in a siliciclastic aquifer system under the context of a rigorous analysis of epistemic uncertainty. The Baton Rouge fault in Louisiana provides an ideal field area to investigate and test the concept of anisotropic fault permeability because of the large amount of historical and field data which exists for the area. In addition, the fault is playing an incompletely understood role in the salinization of a major municipal and industrial source of fresh water north of the fault. The project will test four hypotheses: (1) that the Bense and Person (2006) fault permeability method can be used to characterize the hydraulic properties of the fault, (2) that it is possible to determine whether vertical leakage up the fault plane from the deep saltwater aquifers or lateral leakage across the fault is the dominant cause of salinization, (3) that the Bayesian model averaging (BMA) is a valid method for quantifying salinity prediction uncertainties under a variety of sources of epistemic uncertainty in model parameters and model structure, and (4) that the proposed experimental designs are a valid approach in reducing epistemic uncertainties in salinization predictions. The project outcomes will significantly increase the understanding of the effectiveness of BMA-based experimental designs for reducing epistemic uncertainties in salinization models. The project will also improve the understanding of the Baton Rouge fault in groundwater salinization in a siliciclastic aquifer system. The project provides a means for characterizing the permeability of faults in siliciclastic sequences and for developing techniques for quantifying and reducing uncertainties in the modeling of fluid flow and transport of contaminants across and along faults. The BMA analysis will advance the study of sources of uncertainty in such studies. In particular, the project will significantly advance techniques in the numerical modeling and uncertainty analysis of fluid flow and salinization of the Southern Hills aquifer system and will provide detailed knowledge of the subsurface geology, hydrogeology, and hydrogeochemistry of the region. Saltwater intrusion in the Southern Hills aquifer system is currently an urgent issue for the Louisiana state government, local water utility companies, and industry. The aquifer system currently provides high-quality groundwater that is utilized by the citizens of a four-parish area, but is in danger of being compromised by the introduction of saline waters. The results of project will help guide future salinization modeling and remediation efforts both in the Baton Rouge area and in other similar faulted and unconsolidated siliciclastic aquifer systems. One very practical benefit of the proposed research to society as a whole will be a better understanding of the processes and rates of salinization and the development of a means of remediation of the Southern Hills aquifer system in the greater Baton Rouge area.