Investigation of geophysical electromagnetic computer modelling approaches for infinitesimally thin conductors of curved, complex shapes

研究弯曲、复杂形状的无限薄导体的地球物理电磁计算机建模方法

• 批准号: 543773-2019
• 负责人: Farquharson, Colin
• 金额: $ 1.82万
• 依托单位: Memorial University of Newfoundland
• 依托单位国家: 加拿大
• 项目类别: Engage Grants Program
• 财政年份: 2019
• 资助国家: 加拿大
• 起止时间: 2019-01-01 至 2020-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=680825
• 关键词: Investigation; geophysical; electromagnetic; computer; modelling

Mining is important to Canada's economy, and finding more ore deposits is critical to the future of this industry. Many ore-bodies, and the associated mineralization, can conduct electricity well. A method for finding mineralized zones is therefore to use electromagnetic (EM) fields to induce electric currents to flow within the conductive mineralization, and to measure the magnetic field generated by these currents. The industrial partner for this project, Nova Mining Exploration Solutions, develops new software for modelling the data acquired in such surveys, and offers this software as a service to the exploration industry. The data from EM surveys contain information about the location, depth, size and composition of conductive mineralized zones. To extract this information requires the use of computer modelling techniques. Modelling techniques exist that consider general models of the subsurface. These are useful, but are computationally expensive. However, mineralized zones are often shaped like a warped, creased sheet, i.e., they can have heights and horizontal extents of tens or hundreds of metres, but have a thickness of centimetres. Also, the conductivity of the host rocks can often be so low that it is effectively zero. For these approaches it is possible to describe the induced currents in terms of 2-D functions that exist only in the mineralized zone and not in the host rocks. An implementation of this approach has previously been developed assuming the mineralized zone is shaped like a rectangular plate. This approach has proved to be useful as it is fast to compute and adequately approximates the simpler exploration scenarios. However, the rectangular plate is too simplistic for many scenarios. The proposed research will investigate a new adaptation of the existing approach that includes a new mathematical mapping that will allow the mathematics for the rectancular plate to be transformed to those for an arbitrary sheet. This approach should still be fast to compute, but should now allow for the EM responses of much more realistic mineralized zones to be calculated. The software developed will allow Nova to offer a new service that is at the leading-edge of EM modelling capabilities, thus improving their competitive advantage.

采矿业对加拿大经济很重要，寻找更多矿藏对该行业的未来至关重要。许多矿体以及相关的矿化体都可以很好地导电。因此，寻找矿化带的方法是使用电磁 (EM) 场感应电流在导电矿化层内流动，并测量这些电流产生的磁场。该项目的工业合作伙伴 Nova Mining Exploration Solutions 开发了新软件，用于对此类调查中获取的数据进行建模，并将该软件作为服务提供给勘探行业。电磁勘探数据包含有关导电矿化带的位置、深度、大小和成分的信息。要提取此信息需要使用计算机建模技术。现有的建模技术考虑了地下的一般模型。这些很有用，但计算成本很高。然而，矿化带的形状通常像扭曲的、有折痕的薄片，即它们的高度和水平范围可达数十或数百米，但厚度为厘米。此外，主岩的电导率通​​常很低，实际上为零。对于这些方法，可以用仅存在于矿化带而不存在于主岩中的二维函数来描述感应电流。先前已经开发了这种方法的实施，假设矿化区域的形状像矩形板。这种方法已被证明是有用的，因为它计算速度快并且充分近似更简单的探索场景。然而，矩形板对于许多场景来说过于简单。拟议的研究将调查现有方法的新适应，其中包括新的数学映射，该映射将允许将矩形板的数学转换为任意板材的数学。这种方法的计算速度仍然很快，但现在应该允许计算更现实的矿化区域的电磁响应。开发的软件将使 Nova 能够提供处于电磁建模能力前沿的新服务，从而提高其竞争优势。