Thermo-acoustical-mechanical rock properties under in-situ conditions

原位条件下岩石的热声力学特性

• 批准号: 448842566
• 负责人: Professor Dr.-Ing. Frank Wuttke
• 金额: --
• 依托单位: Arbeitsgruppe Marine und terrestrische Geomechanik und Geotechnik
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/448842566?language=en
• 关键词: Thermo; acoustical; mechanical; rock; properties

The aim of the project is to quantify the coupled thermo-acoustic mechanical behavior of rocks and their microstructural effects between minerals, grains and micro-cracks due to mechanical and thermal loading conditions under simulated in-situ pressure conditions with conducting a series of new experiments in the laboratory as well as the extension of the in-house numerical simulation model by anisotropic material behaviour. The goal is a deep understanding of the change of thermo-mechanical and acoustic rock parameters due to the change in the rock structure due to thermal and mechanical stress. High temperature and mechanical loads influence the microstructure of minerals, grains and induce micro-cracks, which significantly influence the thermo-acoustical-mechanical behavior of rock material. This behavior is even more pronounced and difficult to determine in often existing anisotropic and heterogeneous geomaterials.The investigation of this influence is currently possible only indirectly by ultrasonic waves, which are often calibrated to extracted, ambient pressure-free rock material. This type of thermo-acoustic correlations of rock parameters has been used extensively in geothermic, oil and gas storage and nuclear waste management studies, but this identification is poorly understood empirically and from a microstructural point of view. In addition to the described methods, there is a lack of measuring possibilities for the direct identification of thermal conductivities under in-situ conditions.In order to achieve the specified goals, a new development of the existing experimental triaxial thermo-acoustic-mechanical apparatus by an extension for stationary and transient thermal conductivity and heat capacity measurements under in-situ loads is planned. So far, this type of measurement is not possible within the scientific community. By considering in-situ pressure conditions, the existing rock fabric during the experiment and thus, the coupled thermal-acoustic-mechanical parameters will be different from previous stress-free analyses. In order to translate the experimental results into a theoretical and numerical simulation statement, further extended thermodynamic extended numerical simulations and micro- and meso-scale constitutive modeling of heterogeneous and anisotropic rocks are planned to determine the effective parameter. The novelty of the proposed work concerns: (a) the development of new constitutive models of thermal-acoustical-mechanical behavior of rocks; (b) the validation of the proposed model with new measurements of the thermal conductivity considering in-situ pressure and temperature; (c) the influence of the mineral grain size, particle size distribution, mineral composition, microcracking on the thermal-acoustical-mechanical properties under load and heating and (d) the effects of the microstructure of minerals on thermal-acoustical-mechanical properties.

该项目的目的是量化岩石的耦合热声力学行为及其在模拟原位压力条件下由于机械和热负荷条件而引起的矿物，颗粒和微裂纹之间的微观结构效应，在实验室进行一系列新的实验以及通过各向异性材料行为扩展内部数值模拟模型。目的是深入了解由于热应力和机械应力引起的岩石结构变化而引起的热机械和声学岩石参数的变化。高温和机械载荷作用下，岩石中矿物、颗粒的微观结构发生变化，产生微裂纹，从而对岩石材料的热声力学行为产生重要影响。这种行为在现有的各向异性和非均质地质材料中甚至更加明显和难以确定。目前只能通过超声波间接地研究这种影响，超声波通常被校准为提取的无环境压力的岩石材料。这种类型的岩石参数的热声相关性已被广泛用于地热，石油和天然气储存和核废料管理的研究，但这种识别是很难理解的经验，从微观结构的角度来看。除了所描述的方法，有一个缺乏测量的可能性，在原位conditions. To实现指定的目标，现有的实验三轴热声机械设备的扩展静态和瞬态导热系数和热容量测量原位负载下的直接识别热导率的新发展计划。到目前为止，这种类型的测量在科学界是不可能的。通过考虑现场压力条件，在实验过程中存在的岩石组构，从而耦合的热声力学参数将不同于以前的无应力分析。为了将实验结果转化为理论和数值模拟声明，计划进一步扩展热力学扩展数值模拟和非均质和各向异性岩石的微观和细观尺度本构建模，以确定有效参数。所提出的工作的新奇之处在于：（a）发展了新的岩石热-声-力学行为的本构模型：（B）用考虑原位压力和温度的热导率的新测量值来验证所提出的模型;（c）矿物粒度、粒度分布、矿物成分、（4）矿物的微观结构对热声力学性能的影响。