Tracking Surface Displacement with Satellite InSAR. Another Environmental Factor Under Control

Abstract

The operation of geothermal fields involves the extraction and injection of fluids. This can produce changes in reservoir pressure and possibly deformation of the ground surface, thus creating an undesired consequence on third party assets or potentially hampering the operation itself. Surface displacement and subsidence mapping is usually addressed through repeated survey and in-situ instrumentation. Satellite InSAR is changing this paradigm, as it is possible to retrieve – with the processing of a datastack of remote sensed images – a map of the deformation occurred over the site. The main advantage of satellite InSAR technology for geothermal field monitoring is two-fold. First, in addition to monitoring the site itself, stability of the surrounding area (including slopes and infrastructures in the surrounding) can be tracked and easily updated weekly or bi-weekly. Second, both long- and short-term displacement trends can be captured (including historical analyses) providing a more complete picture of displacement behaviour over time. In this article, the application of InSAR as a provider of consistent ad updated maps is discussed, and cases of comparison between volumetric changes in the reservoir and surface displacement are shared.