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.

采矿对加拿大的经济很重要，寻找更多的矿床对于该行业的未来至关重要。许多矿石和相关的矿化化可以很好地传导电力。因此，找到矿化区域的一种方法是使用电磁（EM）场来诱导电流在导电矿化内流动，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开发了用于对此类调查中获得的数据进行建模的新软件，并为勘探行业提供该软件。来自EM调查的数据包含有关导电矿化区域的位置，深度，大小和组成的信息。要提取此信息，需要使用计算机建模技术。存在考虑地下的一般模型的建模技术。这些很有用，但在计算上很昂贵。但是，矿化区域通常形状像弯曲的薄片，即它们可以具有数十或数百米的高度和水平范围，但具有厚度的厚度为厘米。同样，宿主岩石的电导率通​​常可以很低，以至于有效地为零。对于这些方法，可以用仅在矿化区而不是在宿主岩石中存在的2-D功能来描述诱导电流。假设矿化区的形状像矩形板，则先前已经开发出了这种方法的实现。事实证明，这种方法很有用，因为它可以快速计算并充分近似更简单的探索场景。但是，对于许多情况，矩形板过于简单。拟议的研究将调查现有方法的新适应，其中包括一个新的数学映射，该方法将使直肠板的数学变为任意表的数学。这种方法仍应很快计算，但是现在应该允许计算更现实的矿化区域的EM响应。开发的软件将使Nova能够提供一项在EM建模功能的领先地位的新服务，从而提高其竞争优势。