Temporal Stability of the Transient Electromagnetic Response with Respect to the Development of Monitoring Techniques

在这个项目中，我们开发了一种基于地面到钻孔的瞬变电磁监测技术，用于地下二氧化碳的封存。具有挑战性的方面是随着时间的推移测量的可重复性，以及理解导致二氧化碳引起储集层电导率变化的过程。为了保证测量系统的重复性，关键是要证明测量系统的时间稳定性。因此，我们研究了在具有固定测量布局的已知野外地点组装和拆卸测量设置对测量系统的时间行为的影响。重复测量还将有助于了解记录数据的季节性影响。我们的虚拟电磁实验表明，由于注入600吨二氧化碳，加拿大艾伯塔省布鲁克斯的二氧化碳野外研究站可以预期变化5%。通过现场复查，证明瞬变电磁法基本适用于探测封存过程。最后，我们研究了使用我们的三维反演软件在空间上重建二氧化碳注入的可能性。

In this project, we develop a surface-to-borehole-based transient electromagnetic monitoring technique for the sequestration of CO2 within the subsurface. The challenging aspects are the repeatability of the measurements over time and understanding the processes leading to changes in the conductivity of the reservoir by CO2. To guarantee the repeatability it is crucial to prove the temporal stability of the measuring system. We therefore investigate influences on the temporal behavior of the measuring system arising from assembling and disassembling the measurement setup at a known field site with a fixed survey layout. The repeated measurements will also help to understand seasonal effects on the recorded data. Our virtual electromagnetic experiments have shown that, due to the injection of 600 t of CO2, changes > 5% can be expected at the CO2 field research station in Brooks, Alberta (Canada). A repeat survey on site is intended to prove that the transient electromagnetic method is principally suitable to detect the sequestration process. Finally, we investigate the possibilities of spatially reconstructing the CO2 injection using our three-dimensional inversion software.