Enhancing geothermal exploration with electromagnetic geophysics

地热能有潜力产生大量的能源，而温室气体的排放量最小。加拿大拥有丰富的地热资源，但这些资源目前尚未得到充分利用。地下构造的不确定性是该地区地热开发的主要障碍。这意味着钻探地热勘探威尔斯井具有重大的经济风险。 电磁（EM）地球物理方法通常应用于地热勘探，并使用低频无线电波来测量地下的电阻率。这个参数在地热勘探中很有用，因为它对地下温度和岩石中水的存在非常敏感。大地电磁（MT）法是电磁法的一种，广泛应用于地热勘探，利用天然无线电信号探测地球。它的优点是不需要用发射器产生无线电信号，但来自电力线和其他基础设施的文化电磁噪声可能使人们无法检测到这些自然无线电信号。 拟议的研究将使用MT勘探来调查不列颠哥伦比亚省Lakelse地热前景的地下结构。温泉表明在深处存在地热储层，但需要地球物理成像来绘制地下结构并指导钻探。作为其正在进行的勘探项目的一部分，Borealis GeoPower在Lakelse收集了一系列地球物理数据集。拟议的研究将（1）开发新的策略，以减少MT数据中的文化噪声的影响和（2）改进用于将测量的地球物理数据转换为地下电阻率模型的方法。这项研究将帮助加拿大开发一种能源，有助于减少碳排放及其对气候的影响。

Geothermal energy has the potential to produce significant amounts of energy, with minimal emissions of greenhouse gases. Canada has significant geothermal resources, but these resources are currently underutilized. The major barrier to geothermal development in this region is the uncertainty in subsurface structure. This means that drilling exploratory geothermal wells carries a significant economic risk. Electromagnetic (EM) geophysical methods are commonly applied in geothermal exploration and use low-frequency radio waves to measure the electrical resistivity of the subsurface. This parameter is useful in geothermal exploration because it is very sensitive to subsurface temperature and the presence of water within the rock. The magnetotelluric (MT) method, a type of EM method, is widely used in geothermal exploration and uses natural radio signals to probe the Earth. It has the advantage that there is no need to generate a radio signal with a transmitter, but cultural electromagnetic noise from powerlines and other infrastructure can make it impossible to detect these natural radio signals. The proposed research will use MT exploration to investigate the subsurface structure of a geothermal prospect at Lakelse in British Columbia. Hot springs suggest the presence of a geothermal reservoir at depth, but geophysical imaging is required to map the subsurface structure and guide drilling. Borealis GeoPower have collected a range of geophysical datasets at Lakelse as part of their ongoing exploration project. The proposed research will (1) develop new strategies to reduce the effect of cultural noise in the MT data and (2) improve the methods used to convert the measured geophysical data into a model of the subsurface electrical resistivity. This research will help Canada develop an energy source that can contribute to reducing carbon emissions and their resulting impacts on climate.