Advanced Satellite InSAR Technology For Fault Analysis And Tectonic Setting Assessment. Application To Reservoir Management And Monitoring.

Abstract

Abstract Hydrocarbon reservoir operation, i.e. fluid extraction and injection, are responsible for volumetric changes of reservoir itself resulting in surface deformation phenomena (subsidence or uplift). This processes are controlled by the tectonic framework which is responsible for reservoir compartmentalization and/or fault reactivation. Monitoring surface deformations can provide valuable constraints for modeling the dynamic behavior of a reservoir and help achieve more effective reservoir exploitation with obvious economic benefits. Advanced satellite interferometry represents one of the most valuable and cost-effective techniques, capable of providing high precision and high areal density displacement measurements over long periods of time. Introduction Since 1978, when the first radar images of the Earth's surface were acquired from Synthetic Aperture Radar (SAR) sensors mounted on satellites, SAR interferometry (InSAR) data are gaining increasing attention for their unique technical features and cost-effectiveness, able to provide high-quality, remotely acquired data about surface movements over large areas. In particular, in the late 90's a new technique, called PSInSAR™ (Ferretti et al., 2001), was developed and patented by the Department of Electronics at the Polytechnic University of Milan (POLIMI), considered a real ice-breaker by the InSAR community. By processing multi-temporal radar acquisitions this technique is able to detect millimetre surface deformations, over long periods and large areas. In few years this technique, later improved by Tele-Rilevamento Europa (TRE), a spin-off company of POLIMI, has become a standard tool for studying and monitoring the territory and nowadays is commonly used both for civil protection applications by regional governments, water authorities, research centers and numerous companies in different market sectors. Following a brief recall of some basic InSAR concepts, advanced InSAR techniques support in precisely monitoring surface deformation will be presented through the analysis of two selected case studies. The first one, is relevant to a tectonically active area, where surface displacement measurements provided a valuable support in assessing the evolution of a seismoactive fault system; the second one, relevant to a compartmentalized reservoir in Middle East, shows the effectiveness of Advanced InSAR data in constraining the subsurface deformation related to fluid extraction/injection from underground reservoirs and calibrating hydrocarbon reservoir geomechanical model. Tecnology Overview InSAR is a remote sensing tool that measures ground displacement (Hanssen R., 2001; Kampes B., 2006; Ketelaar V.B.H., 2009). Radar sensors mounted on specific satellites transmit radar signals toward the earth, some of which reflect off objects on the ground, bouncing back to the satellite. These ‘back scattered’ signals are captured by the satellite's sensors and are used to compile radar images of the earth's surface. Radar signals are unaffected by darkness or clouds, in terms of visibility of the land surface. As clouds do not obstruct the passage of the satellite signal, satellite platforms mounting Synthetic Aperture Radar (SAR) systems can function 24 hours a day, 365 days per year.