The effects of fluid flow on the transport properties of faults in Enhanced Geothermal Systems

增强型地热系统中流体流动对断层输运特性的影响

• 批准号: 2295544
• 金额: --
• 依托单位: Heriot-Watt University
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2019
• 资助国家: 英国
• 起止时间: 2019 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2295544
• 关键词: effects; fluid; flow; transport; properties

Successful operation of Enhanced Geothermal Systems (EGSs) requires easy flow of geothermal fluids. Pre-existing faults often provide low permeability pathways for fluid flow. However, such faults may be reactivated during geothermal operations, potentially leading to induced seismicity. Whether or not fault movement leads to induced seismicity depends on the fault frictional properties, which is affected by a range of factors, including the fault rock composition. Both permeability and frictional properties can be affected by the flow-through of the undersaturated solutions involved in geothermal operations, which can lead to mineral dissolution and precipitation, as such changing the (connected) porosity and the fault rock composition. This project aims to quantify how flow-through of undersaturated solutions affects the composition and transport properties of fault materials typical for EGSs, and what the implications are for the frictional properties and thus induced seismicity. The approach adopted involves experimental work, microstructural investigations and microphysical modelling. In addition, the student may be able to work with an industry reactive transport modelling code.The project contributes to a better understanding of the processes active in EGSs, including fault frictional properties and induced seismicity. It is anticipated to result in experimental data on and model predictions of the evolution of fault rock composition and permeability during flow-through of geothermal fluids under a range of conditions with trends identified and quantified. These results can be used as input for studies addressing the evolution of the transport properties of typical fault rocks found in EGCs and the risk of induced seismicity in such systems. This project is directly linked to the successful NERC highlight Topics "Geothermal Power Generated from UK Granites (GWatt)" project, on which the primary supervisor is PI for HWU. The PhD student will learn to: design an experimental program; perform rock deformation experiments; analyse data; perform microstructural analysis, use optical and electron microscopes; formulate microphysical and potentially numerical models; and write scientific papers. Finally, there may be the possibility for an internship with an industrial partner.

增强型地热系统（EGS）的成功运行需要地热流体的容易流动。预先存在的断层通常为流体流动提供低渗透率通道。然而，这种断层可能在地热作业期间重新激活，可能导致诱发地震活动。断层运动是否导致诱发地震取决于断层摩擦性质，而断层摩擦性质又受包括断层岩石成分在内的一系列因素的影响。渗透性和摩擦特性都可能受到地热作业中所涉及的欠饱和溶液的流过的影响，这可能导致矿物溶解和沉淀，从而改变（连接的）孔隙度和断层岩成分。该项目旨在量化如何流过的不饱和溶液的影响的组成和典型的EGS断层材料的传输特性，以及什么样的影响是摩擦性能，从而诱发地震活动。所采用的方法涉及实验工作、微观结构调查和微观物理建模。此外，学生可能能够与一个行业反应运输建模代码。该项目有助于更好地了解活跃在EGS的过程，包括断层摩擦特性和诱发地震活动。预计这将导致实验数据和模型预测的断层岩的组成和渗透性的演变过程中的地热流体在一系列条件下的流动，确定和量化的趋势。这些结果可以作为输入的研究，解决在EGCs中发现的典型断层岩的输运性质的演变和在这样的系统中诱发地震活动的风险。该项目与成功的NERC突出主题“英国花岗岩发电（GWatt）”项目直接相关，该项目的主要主管是HWU的PI。博士生将学习：设计实验方案;进行岩石变形实验;分析数据;进行微观结构分析，使用光学和电子显微镜;制定微观物理和潜在的数值模型;并撰写科学论文。最后，有可能与工业合作伙伴实习。