http://hdl.handle.net/2122/91 Ricerca nel canale cerca http://www.earth-prints.org/simple-search http://hdl.handle.net/2122/4711 Titolo: Mineralogy and geochemical trapping of CO2 in an Italian carbonatic deep saline aquifer: preliminary results<br/><br/>Autori: Cantucci, B.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia; Procesi, M.; Univeristà Roma TRE; Buttinelli, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia; Montegrossi, G.; CNR-IGG Firenze; Vaselli, O.; Dip. Sci. Terra Firenze; Quattrocchi, F.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia<br/><br/>Abstract: CO2 Capture & Storage (CCS) is presently one of the most promising technologiesfor reducing anthropogenic emissions of CO2 . Among the several potential geologi-cal CO2 storage sites, e.g. depleted oil and gas field, unexploitable coal beds, salineaquifers, the latter are estimated to have the highest potential capacity (350-1000 GtCO2 ) and, being relatively common worldwide, a higher probability to be locatedclose to major CO2 anthropogenic sources. In these sites CO2 can safely be retainedat depth for long times, as follows: a) physical trapping into geologic structures; b) hy-drodynamic trapping where CO2(aq) slowly migrates in an aquifer, c) solubility trap-ping after the dissolution of CO2(aq) and d) mineral trapping as secondary carbon-ates precipitate. Despite the potential advantages of CO2 geo-sequestration, risks ofCO2 leakage from the reservoir have to be carefully evaluated by both monitoringtechniques and numerical modeling used in “CO2 analogues”, although seepage fromsaline aquifers is unlikely to be occurring. The fate of CO2 once injected into a salineaquifer can be predicted by means of numerical modelling procedures of geochemicalprocesses, these theoretical calculations being one of the few approaches for inves-tigating the short-long-term consequences of CO2 storage. This study is focused onsome Italian deep-seated (>800 m) saline aquifers by assessing solubility and min-eral trapping potentiality as strategic need for some feasibility studies that are aboutto be started in Italy. Preliminary results obtained by numerical simulations of a geo-chemical modeling applied to an off-shore Italian carbonatic saline aquifer potentialsuitable to geological CO2 storage are here presented and discussed. Deep well data,still covered by industrial confidentiality, show that the saline aquifer, includes sixLate Triassic-Early Jurassic carbonatic formations at the depth of 2500-3700 m b.s.l.These formations, belonging to Tuscan Nappe, consist of porous limestones (mainlycalcite) and marly limestones sealed, on the top, by an effective and thick cap-rock(around 2500 m) of clay flysch belonging to the Liguride Units. The evaluation of thepotential geochemical impact of CO2 storage and the quantification of water-gas-rockreactions (solubility and mineral trapping) of injection reservoir have been performedby the PRHEEQC (V2.11) Software Package via corrections to the code default ther-modynamic database to obtain a more realistic modelling. The main modifications tothe Software Package are, as follows: i) addition of new solid phases, ii) variationof the CO2 supercritical fugacity and solubility under reservoir conditions, iii) addi-tion of kinetic rate equations of several minerals and iv) calculation of reaction sur-face area. Available site-specific data include only basic physical parameters such astemperature, pressure, and salinity of the formation waters. Rocks sampling of eachconsidered formation in the contiguous in-shore zones was carried out. Mineralogywas determined by X-Ray diffraction analysis and Scanning Electronic Microscopyon thin sections. As chemical composition of the aquifer pore water is unknown, thishas been inferred by batch modeling assuming thermodynamic equilibrium betweenminerals and a NaCl equivalent brine at reservoir conditions (up to 135 ̊C and 251atm). Kinetic modelling was carried out for isothermal conditions (135 ̊C), under aCO2 injection constant pressure of 251 atm, between: a) bulk mineralogy of the sixformations constituting the aquifer, and b) pre-CO2 injection water. The kinetic evolu-tion of the CO2 -rich brines interacting with the host-rock minerals performed over 100years after injection suggests that solubility trapping is prevailing in this early stageof CO2 injection. Further and detailed multidisciplinary studies on rock properties,geochemical and micro seismic monitoring and 3D reservoir simulation are necessaryto better characterize the potential storage site and asses the CO2 storage capacity. http://hdl.handle.net/2122/4704 Titolo: RECONSTRUCTION OF POROSITY PROFILE IN AN OFFSHORE WELL<br/><br/>Autori: Montegrossi, G.; CNR-IGG; Vaselli, O.; Dip. Sci. della Terra Firenze; Cantucci, B.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia; Quattrocchi, F.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia<br/><br/>Abstract: We presents the results of a new approach for the reconstruction of thermo-physical properties of deep well from the well log and mineralogical analisys of the outcrops formation. This kind of procedure are generally new, and they are useful for creating the background data for reservoir engeneers and geochemist for modelling a well in order to asses its properties prior of re-opening the well itself for industrial use, such as CO2 sequestration. We used the temperature profile obtained from the well log and the bulk mineralogy analysed from the corresponding formation outcrops. The profile of thermal capacity and conductivity, and porosity and permeability as well, result well constrained and detaile for further use. http://hdl.handle.net/2122/2133 Titolo: MODELING OF THE THERMAL STATE OF MT. VESUVIUS FROM 1631 AD<br/><br/>Autori: Quareni, F.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Bologna, Bologna, Italia; Moretti, R.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia; Piochi, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia; Chiodini, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia<br/><br/>Abstract: The last eruptive event at Mt. Vesuvius occurred in 1944 AD, ending a cycle of continuouseruptive activity started with the sub-plinian event of 1631 AD. The aim of this research is i) tomodel the thermal evolution of the volcanic system from 1631 AD up to the present and ii) toinvestigate the possible process leading the volcano to the current state of quiescence. A finiteelementsoftware is employed to solve the time-dependent energy equation and obtain the thermalfield in the volcanic edifice and the surrounding medium. Volcanological, petrological andgeophysical constraints are used to define the crustal structure beneath the volcanic edifice, themagma supply system active since 1631 AD, and the physico-chemical conditions of magma.Thermodynamic properties of magma and wall rocks have been evaluated from well-establishedthermo-chemical compilations and data from the literature. It is shown that heat transfer due tomagma degassing is required in addition to the heat conduction in order to obtain transient depthtemperaturefields consistent with geochemical observations, high crustal magnetization, and rigidbehavior of the shallow crust as indicated by geophysical data. Surface data of carbon dioxide soilflux coming out from the Mt. Vesuvius crater are taken to constrain such an additional heat flux. Theagreement between modeled and measured temperatures at the crater since 1944 AD proves theconsistency of the model. It is concluded that the present state of quiescence of Mt. Vesuvius ismostly a consequence of the absence of magma supply from the deep reservoir into the shallowersystem. This allows the cooling of residual magma left within the volcanic conduit and the transitionfrom continuous eruptive activity to the condition of conduit obstruction. In this scenario, thehydrothermal system may have developed subsequent to the cooling of the magma within theconduit. Our findings are a direct consequence of the high concentration of CO2 in the most maficVesuvian magmas: the low solubility of CO2, with respect to H2O, enables a high mass flux ofcarbon dioxide through the volcanic edifice. The results of this study are relevant for hazardassessment at Vesuvius and indicate directions for further investigation, such as the role of thehydrothermal system on the thermal energy budget of the volcanic system and its relationships withfluids released by crustal structures likely to host the magmatic reservoir. In general, the role of thehigh concentration of carbon dioxide in magmas should be more questioned and investigated whenstudying the behavior of volcanic systems, particularly in South Italy volcanoes. http://hdl.handle.net/2122/652 Titolo: Could we find any signal of the stratosphere-ionosphere coupling in Antarctica?<br/><br/>Autori: Pietrella, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Kazimirovsky, E. S.; Institute of Solar-Terrestrial Physics, Russian Academy of Sciences, Irkutsk, Russia; De Franceschi, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia; Grigioni, P.; ENEA Casaccia, S. Maria di Galeria (RM), Italy; Scotto, C.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia<br/><br/>Abstract: An investigation searching for a possible coupling between the lower ionosphere and the middle atmosphere in Antarctica is here performed on the basis of stratospheric vertical temperature profiles and ionospheric absorption data observed at the Antarctic Italian Base of Terra Nova Bay (74.69S, 164.12E) during local summer time. The result obtained by applying a multi-regression analysis and a Superimposed Epoch Analysis (SEA) shows a statistically significant ionosphere-stratosphere interaction. In particular, by selecting stratospheric temperature maxima occurring at different heights as the referring epoch for the SEA approach, the ionospheric absorption is found to show a positive and/or negative trend (several days) around it. The tendency for an increasing/decreasing absorption is obtained for temperature maxima occurring below/above the stratospheric level of about 17-19 km, respectively.