Papers by Andrea Tamburini
Snow covers are a seasonal reservoir of water in the solid form. Water mass accumulates during wi... more Snow covers are a seasonal reservoir of water in the solid form. Water mass accumulates during winter, and is released during spring and summer as basal runoff, feeding streamflow of many catchments in temperate areas. The amount of water mass in a snow cover is usually accounted for using the Snow Water Equivalent (SWE, in kg m or mmw.e.), which estimates the mass of liquid water which wold result from the complete melting of the snow cover itself. To calculate this quantity, evaluations of snow depth and bulk snow density are needed. A widely applied solution in conditions of data scarcity implies the measurement of snow depth, and the prediction of bulk snow density using multiple empirical regressions involving, as predictors, weather, climatic or temporal variables, such as air temperature, wind velocity, elevation, snow depth, or the age of the snow cover. Here, we reviewed the relations used in the Literature to estimate mean bulk snow density, and defined a preliminary datas...
Surface deformation monitoring provides unique data for observing and measuring the performance o... more Surface deformation monitoring provides unique data for observing and measuring the performance of producing hydrocarbon reservoirs, for Enhanced Oil Recovery (EOR) and for Carbon Dioxide Capture and Storage (CCS). To this aim, radar interferometry (InSAR) and, in particular, multi-interferogram Permanent Scatterer (PS) techniques are innovative, valuable and cost-effective tools. Depending on reservoir characteristics and depth, oil or gas production can induce surface subsidence or, in the cases of EOR and CCS, ground heave, potentially triggering fault reactivation and in some cases threatening well integrity. Mapping the surface effects of fault reactivation, due to either fluid extraction or injection, usually requires the availability of hundreds of measurement points per square km with millimeter-level precision, which is time consuming and expensive to obtain using traditional monitoring techniques, but can be readily obtained with InSAR data. Moreover, more advanced InSAR techniques developed in the last decade are capable of providing millimeter precision, comparable to optical leveling, and a high spatial density of displacement measurements, over long periods of time without need of installing equipment or otherwise accessing the study area. Until recently, a limitation to the application of InSAR was the relatively long revisiting time (24 or 35 days) of the previous generation of C-band satellites (ERS1-2, Envisat, Radarsat). However, a new generation of X-band radar satellites (TerraSAR-X and the COSMO-SkyMed constellation), which have been operational since 2008, are providing significant improvements. TerraSAR-X has a repeat cycle of 11 days while the two sensors of the COSMO-SkyMed constellation have an effective repeat cycle of just 8 days (the third sensor has already been successfully launched and is presently in the calibration phase). With the launch of the fourth satellite of the constellation, COSMO-SkyMed will have a revisiting time of just 4 days, allowing “near real-time” applications. Additional advantages of the new X-band satellites are: a higher sensitivity to target displacement and a higher spatial resolution. In this paper, we present examples of X-band applications to reservoir monitoring with the aim of highlighting the technical features of the new sensors, the importance of continuous data acquisition and standardized acquisition policies for all InSAR applications.
Very good results have been obtained in the control of unstable slopes with static GPS measuremen... more Very good results have been obtained in the control of unstable slopes with static GPS measurements over the last decade. The GPS technique is particularly suitable for the control of large complex landslide, with annual displacement rate of few centimetres, like deep-seated landslides. Moreover, GPS represents a powerful tool during hydro- geological emergency management, when traditional measurements can't be carried out due to bad weather and visibility conditions. During the last year, a near-real-time differential GPS system has been performed by Enel.Hydro and successfully applied to the control of some of the most important landslides of the Alps. Raw data from permanent GPS stations, located on the unstable slopes and powered by solar cells, are periodically transferred via either radio or GSM modem to a remote Data Acquisition Centre, where they are stored and processed. Both data acquisition and processing are carried out by automatic softwares operating on a PC. The main features of the above mentioned system are described in this paper; some case histories are also presented.
Engineering Geology, 2015
The Carajás mineral province encompasses the world´s largest iron reserves with excavation carrie... more The Carajás mineral province encompasses the world´s largest iron reserves with excavation carried out through open pit benching. Mining operations in the area have significant areas of rock mass movements and surface displacements that potentially lead to slope instabilities with risks to personnel, equipment and production. Instabilities can be expected due to deep excavations in rock masses of low geomechanical quality, blasting practices and heavy precipitation. In this paper, ground instabilities are monitored through an integrated SAR analysis based on a data-stack of 33 TerraSAR-X images. This approach was designed to monitor distinct displacement regimes, ranging from small to high deformation rates, and to map surface changes, based on variations of radar reflectivity. Results were compared with field information (total station/prisms, ground based radar, geological and geomechanical maps), and the approach showed to be effective for monitoring ground deformation in the region. Due to its capabilities (synoptic view, high accuracy, dense grid sampling), the complementary use of spacebased SAR with field monitoring systems proved to be strategic for operational mining planning and risk assessment in this challenging environment.
Image and Signal Processing for Remote Sensing XV, 2009
Monitoring and mapping of active or dormant landslides as well as vulnerable slopes can greatly c... more Monitoring and mapping of active or dormant landslides as well as vulnerable slopes can greatly contribute to both the mitigation of landslide hazards and reduction of their impact. Classical landslide surveying techniques have recently been complemented by satellite data analysis, namely by SAR interferometry. In particular the Permanent Scatterer Interferometry (PSI) technique can be considered complementary to conventional geological and
ABSTRACT Surface deformation monitoring provides unique data for observing and measuring the perf... more ABSTRACT Surface deformation monitoring provides unique data for observing and measuring the performance of producing hydrocarbon reservoirs, for Enhanced Oil Recovery (EOR) and for Carbon Dioxide Capture and Storage (CCS). To this aim, radar interferometry (InSAR) and, in particular, multi-interferogram Permanent Scatterer (PS) techniques are innovative, valuable and cost-effective tools. Depending on reservoir characteristics and depth, oil or gas production can induce surface subsidence or, in the cases of EOR and CCS, ground heave, potentially triggering fault reactivation and in some cases threatening well integrity. Mapping the surface effects of fault reactivation, due to either fluid extraction or injection, usually requires the availability of hundreds of measurement points per square km with millimeter-level precision, which is time consuming and expensive to obtain using traditional monitoring techniques, but can be readily obtained with InSAR data. Moreover, more advanced InSAR techniques developed in the last decade are capable of providing millimeter precision, comparable to optical leveling, and a high spatial density of displacement measurements, over long periods of time without need of installing equipment or otherwise accessing the study area. Until recently, a limitation to the application of InSAR was the relatively long revisiting time (24 or 35 days) of the previous generation of C-band satellites (ERS1-2, Envisat, Radarsat). However, a new generation of X-band radar satellites (TerraSAR-X and the COSMO-SkyMed constellation), which have been operational since 2008, are providing significant improvements. TerraSAR-X has a repeat cycle of 11 days while the two sensors of the COSMO-SkyMed constellation have an effective repeat cycle of just 8 days (the third sensor has already been successfully launched and is presently in the calibration phase). With the launch of the fourth satellite of the constellation, COSMO-SkyMed will have a revisiting time of just 4 days, allowing ``near real-time'' applications. Additional advantages of the new X-band satellites are: a higher sensitivity to target displacement and a higher spatial resolution. In this paper, we present examples of X-band applications to reservoir monitoring with the aim of highlighting the technical features of the new sensors, the importance of continuous data acquisition and standardized acquisition policies for all InSAR applications.
ABSTRACT SqueeSAR represents the most recent advancement of PSInSAR algorithm. By exploiting sign... more ABSTRACT SqueeSAR represents the most recent advancement of PSInSAR algorithm. By exploiting signal radar returns both from Permanent and Distributed Scatterers (PS and DS), it is able to detect millimetre displacements over long periods and large areas and to obtain a significant increase in the spatial density of ground measurement points. SqueeSAR analysis is complementary to conventional geological and geomorphological studies in landslide mapping over wide areas, traditionally based on aerial-photo interpretation and field surveys. However, whenever surface displacement rates are low (mm to cm per year), assessing landslide activity is difficult or even impossible without a long-term monitoring tool, as in the case of Deep-seated Gravitational Slope Deformations (DGSD), typically characterized by large areal extent and subtle surface displacement. The availability of surface displacement time series per each measurement point allows one to have both a synoptic overview, at regional scale, as well as an in depth characterization of the instability phenomena analyzed, a meaningful support to the design of traditional monitoring networks and the efficiency testing of remedial works. When data archives are available, SqueeSAR can also provide valuable information before the installation of any terrestrial measurement system. The Italian authorities increasing interest in the application of SqueeSAR as a standard monitoring tool to help hydrogeological risk assessment, resulted in a national project, Piano Straordinario di Telerilevamento (PST), founded by the Ministry of the Environment. The aim of the project was to create the first interferometric database on a national scale for mapping unstable areas. More than 12,000 ERS and ENVISAT radar scenes acquired over Italy were processed spanning the period 1992-2010, proving that, in less than ten years, radar interferometry has become a standard monitoring tool. Recently, many regional governments in Italy have applied SqueeSAR to map and monitor slope instabilities using ESA-ERS and RADARSAT images. One of the most successful was carried out in the Valle d'Aosta Region (NW Italy). The aim of the study was to support, verify and update the regional landslide inventory. The study covered a time span of about twenty years, from mid 1992 to late 2010. As many unstable areas of the region were reactivated in October 2000 by an intense meteorological event, the surface displacement data provided by traditional monitoring networks were compared at local scale with the displacement measured provided by SqueeSAR. This helped in better understanding the effects of the reactivation of the major landslides identified. Valle d'Aosta Region was the first authority to complete such a project at regional scale and make interpreted data officially available to professionals. Examples of integration of SqueeSAR data with other conventional geological and geomorphological studies at local and regional scale will be presented, with particular focus on DGSDs.
ABSTRACT Remote sensing techniques have been widely used in recent decades to monitor earth surfa... more ABSTRACT Remote sensing techniques have been widely used in recent decades to monitor earth surface displacements related to seismic faults, volcanoes, landslides, aquifers, hydrocarbon fields. In particular, advanced InSAR techniques, such as SqueeSAR™, have already provided unique results thanks to both the extension of the area which can be monitored by satellite data (up to thousands of square km) and the accuracy of the displacement measurements (<1 mm/year). One important field of application for SqueeSAR™ is reservoir monitoring, where surface deformation measurements, coupled to numerical modeling, can improve our understanding of reservoir behavior and help achieve more effective reservoir exploitation with obvious economic benefits. Depending on reservoir depth and the reservoir/overburden rheology, surface deformation data can be used jointly with other measurements to constrain subsurface deformations related to fluid extraction/injection from/into underground formations. One of the most recent applications is relevant to the Tengiz giant oil field, Kazakhstan. In this case, the top of the reservoir is about 3900 m deep. The results obtained by monitoring surface displacements over Tengiz have been used to calibrate a geomechanical model of the reservoir by means of GEPS3D, a state-of-the-art non-linear elasto-plastic Finite Element (FE) code, developed at University of Padova, Italy. This software has been used over the last 10 years for the simulation and prediction of producing reservoir compaction, land subsidence above overexploited aquifers, and, more recently, ground uplift induced by subsurface fluid injection. Numerical simulations have been performed considering the first 14 years of the reservoir production life, from 1993 to 2007. Results of the simulation, expressed in terms of averaged subsidence rate in the period 2004-2007, have been compared with InSAR data. The properties of the site have initially been estimated from data available in literature. Afterwards, a global optimization algorithm has been applied to provide the geomechanical and fluidmechanical parameters exhibiting the best fitting between measured and computed deformation data. Results confirm the importance of high-quality displacement measurement in the estimation of some key geophysical parameters.
2012 IEEE International Geoscience and Remote Sensing Symposium, 2012
ABSTRACT Located in the Alta Badia Valley, a famous tourist area in the Dolomites of northern Ita... more ABSTRACT Located in the Alta Badia Valley, a famous tourist area in the Dolomites of northern Italy, the active Corvara earthslide-earthflow causes damages to critical road infrastructures, as well as ski and other recreational facilities and power lines. The high spatial resolution and the short frequency of revisit time of COSMO-SkyMed system (CSK®), open new opportunities for SAR-based monitoring systems dedicated to natural risks management. The ASI AO funded project “LAWINA” takes advantage from these distinctive features together with non-conventional reflectors, in order to monitor and assess the hazard of such a phenomenon by means of PSI techniques. The particular working context and the complete processing workflow for this specific application, offer opportunity to highlight strengths and weak points of classical approach to PSI and to provides suggestions for an effective use of experimented corners.
2008 Second Workshop on Use of Remote Sensing Techniques for Monitoring Volcanoes and Seismogenic Areas, 2008
This presentation focuses on the results of the application of the Permanent Scatterers Technique... more This presentation focuses on the results of the application of the Permanent Scatterers Technique (PSInSAR¿, an advanced InSAR technique capable of measuring millimetre scale displacements of individual radar targets on the ground) as a method for measuring deformation in volcanic area within the Globvolcano project. In this project, T.R.E. takes part as a service provider for the Deformation Mapping products.
Sustainable earth sciences 2013 proceedings, 2013
ABSTRACT Reservoir monitoring improves our understanding of reservoir behavior and helps achieve ... more ABSTRACT Reservoir monitoring improves our understanding of reservoir behavior and helps achieve more effective reservoir management and prediction of future performance with obvious economic benefits. Volumetric changes in reservoirs due to fluid extraction and injection can induce either subsidence or uplift which can trigger fault reactivation and threaten well integrity (as well as reservoir structural integrity). Depending on the depth of the reservoir and the characteristic of the cap rock, deformation may also be detectable at the surface. Surface deformation monitoring can provide valuable constraints on the dynamic behavior of a reservoir enabling the evaluation of volumetric changes in the reservoir through time, allowing the calibration of geo-mechanical models. Whatever the surveying technique, the detection of millimeter level surface deformation is required to monitor small surface displacement rates, which could impact risk evaluation and environmental impact assessment in oil&gas operations, as well as in geothermal plants.
EAGE Workshop on Geomechanics in the Oil and Gas Industry, 2014
show, with a case study from the InSalah project, Algeria, the benefits of a new application of s... more show, with a case study from the InSalah project, Algeria, the benefits of a new application of surface deformation monitoring using multi-interferogram permanent scatterer techniques, an advance form of radar interferometry.
Energy Procedia, 2011
Surface deformation monitoring provides unique data for observing and measuring the performance o... more Surface deformation monitoring provides unique data for observing and measuring the performance of producing hydrocarbon reservoirs, for Enhanced Oil Recovery (EOR) and for Carbon Capture and Storage (CCS). To this end, radar interferometry (InSAR), particularly multi-interferogram Persistent Scatterer (PS) techniques, such as PSInSAR™, are innovative, valuable and cost-effective tools. Depending on reservoir characteristics and depth, oil or gas production can induce surface subsidence or, in the cases of EOR and CCS, ground heave, potentially triggering fault reactivation and in some cases threatening well integrity. Mapping the surface effects of fault reactivation, due to either fluid extraction or injection, usually requires the availability of hundreds of measurement points per square km with millimeter-level precision, which is time consuming and expensive to obtain using traditional monitoring techniques, but can be readily obtained with InSAR data. Moreover, advanced InSAR techniques developed in the last decade are capable of providing millimeter precision, comparable to optical leveling, and a high spatial density of displacement measurements over long periods of time, without the need for installing equipment or otherwise accessing the study area. Until recently, a limitation to the application of InSAR was the relatively long revisiting time (24 or 35 days) of the previous generation of C-band satellites (ERS1-2, Envisat, Radarsat). However, a new generation of X-band radar satellites (TerraSAR-X and the COSMO-SkyMed constellation), which have been operational since 2008, are providing significant improvements. TerraSAR-X has a repeat cycle of 11 days, while the joint use
International Petroleum Technology Conference, 2014
Hydrocarbon reservoir operation, i.e. fluid extraction and injection, are responsible for volumet... more 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 costeffective techniques, capable of providing high precision and high areal density displacement measurements over long periods of time.
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Papers by Andrea Tamburini