Development of level-set inversion methodology and software for radio imaging (RIM) data

无线电成像法(RIM)是一种地球物理技术，其中电磁(EM)信号(类似于无线电波，但在地面上)在钻孔之间发送。这些电磁信号受岩石类型以及钻孔之间是否有矿化带的影响。因此，在一个钻孔中对发射机的多个位置进行RIM测量，并在另一个钻孔中对接收器的多个位置进行RIM测量，可以提供可用于绘制两个钻孔之间的任何矿化带和矿体的信息。然而，目前的计算机模拟和解释程序是基于一些重要的近似。这些近似使得RIM数据集的计算机建模相对较快。然而，这些近似值也意味着，模拟和解释程序在绘制和圈定任何矿体的地图和圈定方面存在局限性。这里提出的研究旨在产生不使用这些近似的建模和解释方法，而是考虑到地面电磁信号的全部行为。我们将开发计算数学和软件，在考虑到情况的全部电磁物理、针对给定的岩石类型和钻孔之间的矿化的假设模型而测量的RIM数据的情况下，预测RIM数据。我们还将开发解释方法和软件，根据RIM数据集，构建钻孔之间岩石和矿化的模型，即“反转”RIM数据。我们预计，我们将为RIM数据制定一种解释程序，能够提供比目前可能的更准确和更可靠的结果。从RIM数据中获得更清晰、更可靠的地下图像，将使矿产勘探公司能够使用更少的钻孔来圈定和评估未来的矿体。这降低了寻找和开发矿产资源的成本。这反过来又有助于矿产勘探业的健康和竞争力，在纽芬兰、拉布拉多和加拿大，矿产勘探业是重要的财富来源和就业提供者。

The radio imaging method (RIM) is a geophysical technique in which electromagnetic (EM) signals (similar to radio waves, but in the ground) are sent between boreholes. These EM signals are affected by the types of rocks, and whether or not there are zones of mineralization, between the boreholes. Making RIM measurements for many locations of the transmitter in one borehole and many locations of the receiver in the other borehole therefore provides information that could be used to map out any zones of mineralization, and hence ore bodies, between the boreholes. However, current computer modelling and interpretation procedures are based on some significant approximations. These approximations make the computer modelling of a RIM data-set relatively fast. However, these approximations also mean that the modelling and interpretation procedures are limited in how well and how reliably they can map and delineate any ore body. The research proposed here is intended to produce modelling and interpretation methods that do not make use of these approximations but rather take into account the full behaviour of the EM signals in the ground. We will develop the computational mathematics and software for predicting, taking into account the full EM physics of the situation, the RIM data that would be measured for a given hypothesized model of the rock types and mineralization between the boreholes. We will also develop interpretation methodology and software that constructs, from a RIM data-set, a model of the rocks and mineralization between the boreholes, i.e., "inverts" the RIM data. We anticipate that we shall produce an interpretation procedure for RIM data that will be able to provide more accurate and more reliable results than is currently possible. Obtaining a clearer, more reliable picture of the subsurface from RIM data will enable mineral exploration companies to use fewer boreholes to delineate and assess prospective ore bodies. This reduces the cost of finding and developing mineral resources. This in turn helps the health and competitiveness of the mineral exploration industry, which is a significant generator of wealth and provider of employment in Newfoundland and Labrador and in Canada.