Description: Sediment-Hosted Geothermal Systems (SHGSs) are hybrid geological systems, where volcanic and sedimentary domains interact, leading to mixtures of inorganic and organic gases. Typically characterized by geothermal (thermometamorphic or mantle-derived) CO2 and biotic (microbial or thermogenic) CH4, SHGSs occur in sedimentary basins crossed by magmatic intrusions or involved in volcanic plumbing systems. These systems can be of considerable interest for petroleum exploration and natural greenhouse-gas emission studies, but systematic studies for their characterization and worldwide distribution are missing. Here, we provide a review of SHGSs identified so far, and propose methodological criteria for their definition and identification, based on integrated geological and gas-geochemical parameters. We find that SHGSs are typically characterized by: (a) fluids dominated by mantle or decarbonation-methamorphic CO2 (〉50 vol%); (b) considerable amounts of CH4 and heavier hydrocarbons (at least 1.5 vol%, generally up to 30–40 vol%), produced by microbial or thermogenic degradation of organic matter hosted in sedimentary rocks; (c) tectonically active sedimentary basins (back-arc, rift zones and foredeep), generally hosting petroleum fields and within ~300 km from recent or ancient volcanic centers. This analysis resulted in a global map including a first set of 33 SHGSs located in North America, Central and Eastern Europe, Far East, Eastern Oceania and Northern New Zealand, and a second set of potential SHGS prone areas, occurring also in South America, North Africa, Middle East and Kamchatka. The present SHGS map can evolve on the basis of more detailed geological analysis and new gas-geochemical data.

Description: In this paper, we document the evolution of the emergent Panarea dome in the Aeolian islands (Southern Italy), placing particular emphasis on the reconstruction of the explosive events that occurred during the final stage of its evolution. Two main pyroclastic successions exposing fall deposits with different compositions have been studied into detail: the andesitic Palisi succession and the basaltic Punta Falcone succession. The close-in-time deposition of the two successions, the dispersal area and grain-size distribution of the deposits account for their attribution to vents located in the western sector of the present island and erupting almost contemporaneously. Vents could have been aligned along NNE-trending regional fracture systems controlling the western flank of the dome and possibly its collapse. Laboratory analyses have been devoted to the characterization of the products of the two successions that have been ascribed to vulcanianand to strombolian-type eruptions respectively. The vulcanian eruption started with a vent-clearing phase that occurred by sudden decompression of a pressurized magma producing ballistic bombs and a surge blast and the development of a vulcanian plume. Vulcanian activity was almost contemporaneous to stromboliantype fall-out eruptions. The coeval occurrence of basaltic and andesitic eruptions from close vents and the presence of magmatic basaltic enclaves in the final dacitic lava lobe of the dome allow us to speculate that the intrusion of a basaltic dyke played a major role in triggering explosive eruptions. The final explosive episodes may have been caused by extensional tectonics fracturing the roof of a zoned shallow magma chamber or by the intrusion of a new basaltic magma into a more acidic and shallow reservoir. Intrusion most likely occurred through the injection of dykes along the western cliff of the present Panarea Island inducing the collapse of the western sector of the dome.

Description: Published

Description: 797-811

Description: JCR Journal

Description: restricted

Description: Soon after a 222Rn and 220Rn survey in soil gases, performed (June 2005) in the frame of the Diffuse Degassing in Italy risk assessment project, a moderate earthquake (Mw=4.6) occurred in the Anzio offshore, on August, 22, 2005, only 5 miles from the Tor Caldara Diffuse Degassing Structure (DDS onward). Having available the pre-earthquake 222Rn and 220Rn grid-map on around 50 soil-gas points and being 222Rn both a stress-pathfinder and a discriminative component of activated-faults, a mirrorlike survey was repeated on the same 50 sites, soon after the close earthquake. Later, during a quiescent-aseismic period (December, 2005), a CO2 flux survey was performed for the same 50 sites, adding detailed measurements (more than 100 sites) for the highest flux sectors. The aim of this survey was both to have an overall picture of the background CO2 flux and to calculate the total budget of CO2 flux throughout the DDS, to better interpret the 222Rn and 220Rn areal surveys before and after the seismic event. Herewith, we distinguish the contribution of organic, diffusive and advective CO2 flux. Hints of convection and strong degassing linked to the fracture field, inside the DDS, have been envisaged on selected points, where continuous monitoring stations could be strategic, for seismic, volcanic and NGH surveillance. Despite we found higher 222Rn values in soils after the earthquake, suggesting an enhanced local degassing probably linked to a stress signal throughout the DDS as a whole, the results highlight an unmodified shape and location of the 222Rn anomalies before and after the earthquake. This evidence excludes both that the activated seismogenic segment has affected in some ways both the DDS degassing patterns and that fracture field changed. A similar result could be expected if the activated fault was oriented along the DDS itself and reached the surface. This evidence is well correlated with the reconstructed focal mechanism of the earthquake, pertaining to the transfer structure of the Ardea Graben , located along a peripheral sector of the degassing Alban Hills volcano and intersecting the DDS Tor Caldara itself. The shape and location of 222Rn anomalies inside the DDS for both the surveys are strictly inversely correlated with the areal CO2 flux data. The geometry of the degassing pathways is probably linked to the barrier action (sealing power) of the clays cropping out in the study area. These clays are generated by the strong leaching of the outcropping sedimentary Pleistocene rocks due to the huge flux of volcanic gas -rich fluids.

Description: Published

Description: Perugia, Italy

Description: 2.4. TTC - Laboratori di geochimica dei fluidi

Description: open

Description: Abstract: Soon after a 222Rn and 220Rn survey in soil gases, performed (June 2005) in the frame of the “Diffuse Degassing in Italy” risk assessment project, a moderate earthquake (Mw=4.6) occurred in the Anzio offshore, on August, 22, 2005, only 5 miles from the Tor Caldara “Diffuse Degassing Structure” (DDS onward). Having available the pre-earthquake 222Rn and 220Rn grid-map on around 50 soil-gas points and being 222Rn both a stress-pathfinder and a discriminative component of activated-faults, a mirror-like survey was repeated on the same 50 sites, soon after the close earthquake. Later, during a quiescent-aseismic period (December, 2005), a CO2 flux survey was performed for the same 50 sites, adding detailed measurements (more than 100 sites) for the highest flux sectors. The aim of this survey was both to have an overall picture of the “background” CO2 flux and to calculate the total budget of CO2 flux throughout the DDS, to better interpret the 222Rn and 220Rn areal surveys before and after the seismic event. Herewith, we distinguish the contribution of organic, diffusive and advective CO2 flux. Hints of convection and strong degassing linked to the fracture field, inside the DDS, have been envisaged on selected points, where continuous monitoring stations could be strategic, for seismic, volcanic and NGH surveillance. Despite we found higher 222Rn values in soils after the earthquake, suggesting an enhanced local degassing probably linked to a stress signal throughout the DDS as a whole, the results highlight an unmodified shape and location of the 222Rn anomalies before and after the earthquake. This evidence excludes both that the activated seismogenic segment has affected in some ways both the DDS degassing patterns and that fracture field changed. A similar result could be expected if the activated fault was oriented along the DDS itself and reached the surface. This evidence is well correlated with the reconstructed focal mechanism of the earthquake, pertaining to the transfer structure of the Ardea Graben , located along a peripheral sector of the degassing Alban Hills volcano and intersecting the DDS Tor Caldara itself. The shape and location of 222Rn anomalies inside the DDS for both the surveys are strictly inversely correlated with the areal CO2 flux data. The geometry of the degassing pathways is probably linked to the “barrier action” (sealing power) of the clays cropping out in the study area. These clays are generated by the strong leaching of the outcropping sedimentary Pleistocene rocks due to the huge flux of volcanic gas -rich fluids.

Description: Submitted

Description: Accepted N. 2006JB004580 Solid Earth.

Description: 4.5. Degassamento naturale

Description: JCR Journal

Description: open

Description: Stabilize and reduce the atmospheric concentration of anthropogenic greenhouse gases is one of the principal goal that have to be accomplished in short time, in order to reduce the climate changes and the global warming, following the World Energy Outlook 2007 program by IEA. The most promising remedy, proposed for large CO2 sources like thermoelectric power plants, refineries and cement industries, is to separate the flue gas capturing the CO2 and to store it into deep sub-surface geological reservoirs, such as deep saline aquifers, depleted oil and gas fields and unminable coal beds. Among these options, deep saline aquifers are considered the reservoirs with the larger storage potentiality, as a consequence of a wide availability with respect to deep coal seems, depleted oil fields and gas reservoirs. The identification of a possible storage site necessarily passes through the demonstration that CO2 can be injected in extremely safe conditions into geological deep formations, with impermeable caprock above the aquifer/s, which physic-chemical-mineralogical conditions are useful to a better mineral and solubility trapping as well as the hydrodynamic or physical/ structural ones. In order to support the identification of potential storage reservoirs in Italy, INGV jointly with CESI RICERCA S.p.A. accomplished a detailed reworking of available geological, geophysical, geochemical and seismological data, in order to support the existing European GESTCO as well as the CO2GeoCapacity projects. Aim of this work is to establish some site selection criteria to demonstrate the possibility of the geological storage of CO2 in Italy, even if it is located in an active geodynamical domain. This research started from the study of 7575 wells drilled on Italian territory during the last 50 years for gas/oil and geothermal exploration. Among this data-set as a whole, only 1700 wells (deeper than 800 m) have been selected. Only 1290 of these wells have a public-available composite log and fit with the basic prerequisites for CO2 storage potential, mostly as deep saline aquifer/s presence. Wells data have been organized into a geodatabase containing information about the nature and the thickness of geological formations, the presence of fresh, saline or brackish water, brine, gas and oil, the underground temperature, the permeability, porosity and geochemical characteristics of the caprock and the reservoirs lithologies. Available maps, seismic and geological profiles containing or closer to the analyzed wells have been catalogued too. In order to constrain the supercritical behaviour of the CO2 and to prevent the escape of gaseous CO2 to the surface, a first evaluation of the caprock presence and quality has been done on these selected wells. Using a numerical parameterization of the caprock lithologies, a “Caprock Quality Factor” (Fbp) has been defined, which clustered the wells into 5 different classes of caprock impermeability (ranging between the lowest 1 to highest 5). The analysis shows that more than 50% of the selected wells have an Fbp Factor between 4 and 5 (good and optimal quality of caprock), and are mostly located in foredeep basins of the Alps-Apenninic Chain. The geodatabase also includes: i) the seismogenetic sources (INGV DISS 3.0.4 Database of Individual Seismogenetic Sources), ii) an elaboration of seismic events catalogues (INGV CFTI, CPTI04, NT4.1), iii) the Diffuse Degassing Structures (DDS), as part of the INGV project V5 diffuse degassing in Italy geodatabase, considered as “CO2 analogue” field-tests, iv) the distribution of the thermal anomalies on the Italian Territory, linked to the presence of volcanic CO2 emissions, in order to consider the CO2 diffuse degassing risk assessment on the Italian territory Successively it has been created a geodatabase on the nature and quality of deep aquifers for the high-ranking wells sub-dataset (where the aquifers data are available), containing the following parameters: i) presence of one or more aquifers deeper than 800 meters; ii) thickness of the aquifer/s; iii) lithology of the reservoir/s; iv) available chemical analysis; v) distance from closer power plants or other anthropogenic CO2 sources.The final aim of these work is to help to find potential areas in Italy where CO2 storage feasibility studies can be done. In these cases it is necessary to implement the knowledge by: i) better evaluation of saline aquifer quality; ii) estimation of CO2 storage capacity by 3D-modeling of deep crustal structures; iii) fluid-dynamic and geochemical modelling of water-rock-CO2 interaction paths.

Description: Published

Description: Vienna, Austria

Description: 2.4. TTC - Laboratori di geochimica dei fluidi

Description: open

Description: The abstracts herein – collected for the 34th Course of the International School of Geophysics, held in Erice, Italy (“Ettore Majorana” Foundation and Centre for Scientific Culture, 25-30 September, 2010) – focus on geophysical, geological and geochemical methods applied to the planning of the soundest energy mix in densely populated countries, where the coexistence of different technologies requires unique underground facilities and resources. In the framework of IEA and EU programmes, where the concepts of “smart grids” and “smart cities” are prevailing, we rather propose the concept of “smart region” planning the use of both underground and surface areas in a new social-energetic paradigm of “zero kilometer” life. The coexistence of geological storage of CO2 and natural gas, geothermics and, possibly, nuclear waste temporary storage (near surface or geological) is today necessary owing to the progressive decrease of space and resources. In this context, the following technologies turn out to be very important: renewables (geothermal energy), nuclear power, clean coal technologies via CO2 Capture and Storage (CCS), Enhanced Oil Recovery (EOR), Enhanced Coal Bed Methane (ECBM), non-conventional gas exploitation, and seasonal storage of natural gas (also for strategic reserves). These technologies have been recently emphasized in Italy by the Ministry of Economic Development and by the Ministry of the Environment and Territory, as well as by research institutions such as INGV and CNR. Key topics addressed during the Course were: • Geological storage and disposal: assessment of available volume and structures. • Subsurface geological resources: management of potential conflicts among various technologies. • Geological site characterization and risk assessment for policy makers and regulators: the role of the energy industry. • New high tech frontiers for geothermal power production. • New concepts in nuclear waste disposal. • Numerical simulation software for geothermal exploration, geological storage and nuclear waste disposal. • Sharing subsurface data coming from oil & gas and geothermal exploration. • High resolution characterization of shallow aquifers and reservoirs: multi-strata exploitation by different energy technologies. • Case histories and natural analogues: “learning by doing” and “acceptable risk” concepts. The 34th Course of the International School of Geophysics is dedicated to students and young contract researchers starting their carreers in a period of energetic-environmental global crisis. Although their scientific contribution is of high quality, they are usually underpaid in public research institutions with respect to volatile staff of some international organizations who, making use of the results of governmentfunded research, make final decisions on low-carbon energy technologies.

Description: Published

Description: 1-102

Description: 1.8. Osservazioni di geofisica ambientale

Description: N/A or not JCR

Description: open

Description: In densely populated countries there is a growing and compelling need to use underground for different and possibly coexisting technologies to produce ‘‘low carbon’’ energy. These technologies include (i) clean coal combustion merged with CO2 Capture and Storage (CCS); (ii) last-generation nuclear power or, in any case, safe nuclear wastes disposal, both ‘‘temporary’’ and ‘‘geological’’ somewhere in Europe (at least in one site): Nuclear wastes are not necessarily associated to nuclear power plants; (iii) safe natural gas (CH4) reserves to allow consumption also when the foreign pipelines are less available or not available for geopolitical reasons and (iv) ‘‘low-space-consuming’’ renewables in terms of Energy Density Potential in Land (EDPL measured in [GW h/ha/year]) as geothermics. When geothermics is exploited as low enthalpy technology, the heat/cool production could be associated, where possible, to increased measures of ‘‘building efficiency’’, low seismic risks building reworking and low-enthalpy heat managing. This is undispensable to build up ‘‘smart cities’’. In any case the underground geological knowledge is prerequisite. All these technologies have been already proposed and defined by the International Energy Agency (IEA) Road Map 2009 as priorities for worldwide security: all need to use underground in a rational and safe manner. The underground is not renewable in most of case histories [10,11]. IEA recently matched and compared different technologies in a unique ‘‘Clean Energy Economy’’ improved document (Paris, November 16–17, 2011), by the contribution of this vision too (see reference). In concert with ‘‘energy efficiency’’ improvement both for plants and buildings, in the frame of the ‘‘smart cities’’ scenarios, and the upstanding use of ‘‘energy savings’’, the energetic planning on regional scale where these cities are located, are strategic for the year 2050: this planning is strongly depending by the underground availability and typology. Therefore, if both literature and European Policy are going fast to improve the concept of ‘‘smart cities’’ this paper stresses the concept of ‘‘smart regions’’, more strategic than ‘‘smart cities’’, passing throughout a discussion on the synergic and conflicting use of underground to produce energy for the ‘‘smart regions’’ as a whole. The paper highlights the research lines which are urgent to plan the soundest energy mix for each region by considering the underground performances case by case: a worldwide mapping, by GIS tools of this kind of information could be strategic for all the ‘‘world energy management’’ authorities, up to ONU, with its Intergovernmental Panel on Climate Change (IPCC), the G20, the Carbon Sequestration

Description: Published

Description: 393-412

Description: JCR Journal

Description: reserved

Description: A geochemical survey, in shallow aquifers and soils, has been carried out to evaluate the feasibility of natural gas (CH4) storage in a deep saline aquifer at Rivara (MO), Northern Italy. This paper discusses the areal distribution of CO2 and CH4 fluxes and CO2, CH4, Rn, He, H2 concentrations both in soils and shallow aquifers above the proposed storage reservoir. The distribution of pathfinder elements such as 222Rn, He and H2 has been studied in order to identify potential faults and/or fractures related to preferential migration pathways and the possible interactions between the reservoir and surface. A geochemical and isotopic characterization of the ground waters circulating in the first 200 m has allowed to investigation of (i) the origin of the circulating fluids, (ii) the gas–water–rock interaction processes, (iii) the amount of dissolved gases and/or their saturation status. In the first 200 m, the presence of CH4-rich reducing waters are probably related to organic matter (peat) bearing strata which generate shallowderived CH4, as elsewhere in the Po Plain. On the basis of isotopic analysis, no hints of thermogenic CH4 gas leakage from a deeper reservoir have been shown. The d13C(CO2) both in ground waters and free gases suggests a prevalent shallow origin of CO2 (i.e. organic and/or soil-derived). The acquisition of preinjection data is strategic for the natural gas storage development project and as a baseline for future monitoring during the gas injection/withdrawing period. Such a geochemical approach is considered as a methodological reference model for future CO2/CH4 storage projects.

Description: Published

Description: 3-22

Description: 4.5. Studi sul degassamento naturale e sui gas petroliferi

Description: JCR Journal

Description: restricted

Description: One of the most promising options to stabilize and reduce the atmospheric concentration of greenhouse gases is Carbon Capture and Storage (CCS). This technique consists of separating CO2 from other industrial flue gases and storing it in geological reservoirs, such as deep saline aquifers, depleted oil and/or gas fields, and unminable coal beds. A detailed reworking of all available Italian deep-drilling data was performed to identify potential storage reservoirs in deep saline aquifers. Data were organized into a GIS geo-database containing stratigraphic and fluid chemistry information as well as physiochemical characteristics of the geological formations. Caprock efficiency was evaluated via numerical parameterization of rock permeabilities, defining the “Caprock Quality Factor” (Fbp) for each well. The geo-database also includes strategic information such as the distribution of deep aquifers, seismogenic sources and areas, seismic events, Diffuse Degassing Structures, heat flow, thermal anomalies, and anthropogenic CO2 sources. Results allow the definition of potentially suitable areas for future studies on CO2 geological storage located in the fore-deep domains of the Alps and Apennines chains, where efficient marly-to-clayish caprocks lie above deep aquifers hosted in sands or limestones. Most of them are far form seismogenic sources and Diffuse Degassing Structures.

Description: Published

Description: 2968-2983

Description: 3.8. Geofisica per l'ambiente

Description: 4.4. Scenari e mitigazione del rischio ambientale

Description: 5.4. Banche dati di geomagnetismo, aeronomia, clima e ambiente

Description: 5.5. TTC - Sistema Informativo Territoriale

Description: JCR Journal

Description: reserved

Description: L’area della riserva naturale Monterano è ubicata nel settore occidentale del distretto vulcanico Sabatino, in un contesto geochimico caratterizzato dalla presenza di numerose manifestazioni termali ed emissioni gassose (Baldi et al., 1973; Dall’Aglio et al., 1994; Minissale et al., 1997; Minissale, 2004). Tali manifestazioni sono frequenti nel settore peri-Tirrenico dell’Italia centrale (Duchi e Minissale, 1995; Chiodini et al., 1995, 1999; Barberi et al., 2007; Frondini, 2008; Frondini et al., 2009) e sono comunemente associate all’attività magmatica seguita ai movimenti tettonici distensivi avvenuti durante il Neogene (Buonasorte et al., 1987; Barberi et al., 1994). Dal punto di vista geologico i prodotti vulcanici del distretto Sabatino ricoprono una sequenza sedimentaria che comprende, dal basso verso l’alto: 1) la formazione dei Calcari Mesozoici, 2) il Flysch Tolfetano di età Cretacico-Oligocenica e 3) la formazione delle sabbie e argille del Miocene e Quaternario. I Calcari Mesozoici sono sede di un acquifero termale, esteso su scala regionale, a composizione Ca-SO4(HCO3), e di una fase gassosa ricca in CO2. Le vulcaniti sabatine e la formazione del Flysch Tolfetano contengono acquiferi freddi di limitate dimensioni, a composizione rispettivamente Ca(Na, K)-HCO3 e Ca(Mg)-HCO3. Le formazioni pre-vulcaniche sono state interrotte nella loro continuità laterale da faglie distensive che hanno generato un’alternanza di alti e bassi strutturali (horst e graben). E’ in corrispondenza delle zone di alto strutturale e lungo i bordi tra alti e bassi che si osserva la risalita di fluidi di origine profonda (acque termali e gas) che possono mescolarsi con le acque fredde superficiali e/o raggiungere la superficie. Il presente studio si propone di fornire un’accurata caratterizzazione geochimica dei fluidi (acque e gas) presenti all’interno della riserva naturale Monterano, al fine di stabilirne l’origine, le modalità di circolazione e risalita verso la superficie e i processi di interazione acqua–gas–roccia.

Description: Published

Description: restricted