Development of the induced polarization theory with application to exploration of strategic raw materials

激发极化理论的发展及其在战略原材料勘探中的应用

• 批准号: 425975038
• 负责人: Professor Dr. Andreas Weller
• 金额: --
• 依托单位: Institut für Geophysik
• 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/425975038?language=en
• 关键词: Development; induced; polarization; theory; application

Within last two decades, Spectral Induced Polarization (SIP) method attracts researchers because it allows to remotely investigate interface properties of geo-materials. As a result, SIP is increasingly used in hydrogeology, contaminant hydrology, geotechnics and mineral exploration. However, to date many points in the physical and chemical theory of Induced Polarization (IP) phenomena are contradictory and understudied. First, the role of different mechanisms (interfacial mechanisms, diffusion of p- and n-charge carriers, electromagnetic induction, and Maxwell-Wagner effect) in polarization of metallic particles (MP) is unclear. Second, each mechanistic model of rock polarization describes only one mechanism (the Stern layer of the Electrical Double Layer polarization, the membrane polarization, or the Maxwell-Wagner polarization). No model includes all of the mechanisms. The objectives of the project are to fill the above-mentioned gaps. We expect: - to develop an unified model of IP of metallic particles;- to improve the mechanistic models of rock polarization.In order to validate these models, we will carry out an extensive series of laboratory experiments with natural samples of magmatic and hydrothermally altered rocks typical of some economically important ore deposits. However, natural samples (being highly heterogeneous) are always poorly sorted in terms of mineral composition and pore structure. Therefore, we will use well-controlled synthetic samples to clarify some aspect of the new models. As a result, we will compile a new extensive database of SIP data available for the scientific community for reuse.Moreover, to test the models we will reproduce numerically the phenomena responsible for IP based on solution of the Nernst-Plank - Poisson-Boltzmann differential equations with the COMSOL Multiphysics package. In addition, we address two methodological aspects of SIP data processing. First, it can be assumed that not all polarization responses indicate a Debye character. However, experimental data are frequently fitted with a Debye Decomposition (DD) procedure. We propose to extend the DD approach for non-Debye relaxation case. Then, field surveys are typically performed with the Time Domain (TD) technique, whereas petrophysical researches are carried out with the Frequency Domain (FD) technique. So, TD and FD data must be compared. However, for real lab, and, especially, field data the TD – FD transformation is not straightforward. For this reason, we plan to improve the TD - FD transformation technique. Finally, the theoretical and methodological results will be applied to ore exploration. We propose to develop a prototype of TD IP logging instrument, to test it within ore deposits, and to assess the information output of IP logging. If this task is successful, we believe to obtain a promising technology for ore exploration, which will be demanded by commercial and state enterprises.

在过去的二十年里，光谱诱导偏振（SIP）方法吸引了研究人员，因为它可以远程研究地质材料的界面特性。因此，SIP 越来越多地应用于水文地质学、污染物水文学、岩土工程和矿产勘探。然而，迄今为止，诱导极化（IP）现象的物理和化学理论中的许多观点都是相互矛盾的并且尚未得到充分研究。首先，不同机制（界面机制、p 和 n 电荷载流子的扩散、电磁感应和麦克斯韦-瓦格纳效应）在金属颗粒 (MP) 极化中的作用尚不清楚。其次，岩石极化的每种机制模型仅描述一种机制（双电层极化的斯特恩层、膜极化或麦克斯韦-瓦格纳极化）。没有模型包含所有机制。该项目的目标是填补上述空白。我们期望： - 开发金属颗粒IP的统一模型； - 改进岩石极化的机制模型。为了验证这些模型，我们将利用一些具有重要经济意义的矿床的典型岩浆和热液蚀变岩石的天然样品进行一系列广泛的实验室实验。然而，天然样品（高度异质）在矿物成分和孔隙结构方面总是分类不佳。因此，我们将使用控制良好的合成样本来阐明新模型的某些方面。因此，我们将编译一个新的广泛的 SIP 数据数据库，供科学界重复使用。此外，为了测试模型，我们将基于 Nernst-Plank - Poisson-Boltzmann 微分方程与 COMSOL Multiphysics 软件包的求解，以数值方式再现导致 IP 的现象。此外，我们还讨论了 SIP 数据处理的两个方法方面的问题。首先，可以假设并非所有偏振响应都表明德拜特征。然而，实验数据经常采用德拜分解 (DD) 程序进行拟合。我们建议将 DD 方法扩展到非德拜松弛情况。然后，现场勘测通常使用时域（TD）技术进行，而岩石物理研究则使用频域（FD）技术进行。因此，必须对TD和FD数据进行比较。然而，对于真实的实验室，尤其是现场数据，TD – FD 转换并不简单。为此，我们计划改进TD-FD变换技术。最后，理论和方法结果将应用于矿石勘探。我们建议开发 TD IP 测井仪器原型，在矿床中对其进行测试，并评估 IP 测井的信息输出。如果这项任务成功，我们相信将获得一项有前途的矿石勘探技术，这将是商业和国有企业所需要的。