Measuring Surface Deformation using Satellite Radar Sensors - a Powerful Tool in Permanent Reservoir Monitoring

Surface deformation monitoring can provide valuable constraints on the dynamic behaviour of a reservoir, by allowing the evaluation of volume/pressure changes with time, as well as an estimation of reservoir permeability. Levelling campaigns, tiltmeters, GPS and InSAR are all geodetic techniques used to detect and monitor surface deformation phenomena. Among them, InSAR data from satellite radar sensors are gaining increasing attention for their unique technical features and cost-effectiveness. In particular, Permanent Scatterer InSAR (PSInSAR™) is an advanced InSAR technique, developed in the late nineties, capable of providing very precise 1D displacement measurements along the satellite line-of-sight (LOS) and high spatial density (typically exceeding 100 measurement points/sqkm) over large areas, by exploiting point-wise radar targets already available on ground. Recently, some significant advances have been reported in InSAR data processing that can further increase the quality and the effectiveness of this data source for reservoir monitoring: (a) the development of new InSAR algorithms and in particular the so-called SqueeSAR™ approach, which allows a significant increase in the spatial density of measurement points; (b) the availability of an increased number of satellite radar sensors characterized by higher sensitivity to surface deformation, higher spatial resolution, and better temporal frequency of acquisition.