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There is a growing interest in the characterization of mining residues, both for environmental assessments and critical raw materials recovery. The lack of sufficient in situ samples hampers an effective geostatistical modelling of material concentrations variability. This paper proposes a method to characterize the aluminum spatial variability in a mine residue from remote sensing data and imprecise information from daily dumping procedures. The method is proposed for the mapping of aluminum within a Greek bauxite residue, using Sentinel-2 imagery. The spatial correlation between metal concentrations and remote sensing indicators (e.g., spectral band ratios) is the premise for mapping aluminum varieties. The proposed method is based on Conditional Gaussian Co-Simulation, where Sentinel-2 images can be used as auxiliary variables. Simulation results are compared with the Co-kriging estimation method. To perform the Co-kriging estimation, the same conditions as simulation are used (same inputs, models, and neighborhoods). Simulation results quantified the metals variability in mining residues, presenting the metal concentration of piled materials in two time periods. For results validation and selecting the best map, fourteen validation samples were used. For the best representative maps of aluminum concentration, a correlation coefficient of about 0.7 between the validation data and obtained aluminum concentration map was obtained.

Ornamental stones are natural building materials, extracted from quarries, which need to be cut and processed sustainably. Natural discontinuities adversely affect the sawing/cutting of blocks into commercial-size slabs. This work presents a 3D optimization algorithm for the sawing/cutting of ornamental stone blocks. The developed algorithm is based on 3D modeling of discontinuities as data input. The algorithm search for the intersection between a 3D cutting grid formed of a determined size of slabs and the model of discontinuities leading to calculate the recovery ratio considering several cutting orientations and displacements of the 3D cutting grid. The algorithm was coded in a program named SlabCutOpt that allows speed problem solving. SlabCutOpt was implemented on a real case study of a commercial-size limestone block extracted from a quarry in Italy. A number of 37 different commercial-sizes of slabs forming 37 cutting grids were tested to investigate the optimum results in geo-environmental direction (recovery ratio) and economic direction (revenue). The findings revealed that a certain slab size gave the optimum recovery ratio, whilst another slab size provided the optimum revenue.

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This paper presents a 3D algorithm for finding the optimum cutting direction in ornamental stone quarries aiming at maximizing the recovery ratio of blocks through tackling the fracture problem that causes material and economic loses. The presented algorithm is based on 3D deterministic fracture modeling or mapping data and considers new parameters: i) displacement of the cutting grid; (ii) material lost by quarrying; (iii) irregularity of the tested area; (iv) and subdivision of large quarrying area. The algorithm searches for the optimum cutting direction and displacement of the cutting grid that maximizes the number of non-fractured blocks. The algorithm was coded in a software package named BlockCutOpt. This paper presents BlockCutOpt results applied in two case studies of different characteristics. The first case study was a limestone bench where fractures were modeled deterministically using Ground Penetrating Radar (GPR) survey. The second case study was in a very large area of granite deposit where the regional fractures were mapped using the aerial photogrammetry method (literature data). BlockCutOpt was found a fast tool for finding the optimum cutting pattern in the presented case studies. The results showed that the optimum cutting direction of blocks can vertically (within different strata) and horizontally (within very large scale area) vary, giving geometric information about the cutting grid design that optimizes the number of non-fractured blocks.

Summary This paper presents preliminary results of a new T2Well version, coupled with modified ECO2M equation of state, able to simulate three-phase flow in the wellbore with the coexistence of liquid and gaseous CO2, with the final aim to be able to detect possible operational problems caused by phase changes during transient flow periods.

The overall goal of this work was to determine the concentration levels and the potential ecological risks of 30 polycyclic aromatic hydrocarbons in the Persian Gulf sediments, Iran. The study also predicted the bioaccumulation of PAHs using the Monte Carlo simulation. For these goals, 68 surface sediment samples were collected from the Persian Gulf in January 2017. Then, the experiments were performed with Soxhlet system, chromatographic column and GC-MS instrument. According to the Canadian Sediment Quality Guidelines, 35.29% of sampling sites exhibited high potential adverse biological effects and 79.41% of samples have a low probability of toxicity. The mean bioaccumulated concentrations of carcinogenic PAHs in the Persian Gulf were predicted as 207.78 ± 262.23, 116.06 ± 146.47 and 69.26 ± 87.41 ng g–1 for mollusks, shrimps and crabs, respectively. The mean Toxic Equivalency and Mutagenic Equivalent Quotient for sediments was 702.06 ± 1012.37 and 500.37 ± 665.71 ng g−1, respectively. The 95th percentile carcinogenic and non-carcinogenic risks calculated for children and adults were lower than the threshold values of 10−6 and 1.0, respectively, revealing no potential health risk. The highest potential risks for toxicity were observed at sampling sites close to the Nowruz oil field and Mahshahr petrochemical economic zone based on the highest TEQcarc and MEQcarc values in this area.

In geostatistical analysis, often the data have different support (volume). Data with different supports can be treated separately or together but in a consistent way. In many applications, data are considered as point variable averaged over the sample volume. Regularisation of data has a significant impact on variograms and geostatistical estimations. Two methods of managing data with different supports (“integrating”) are compared: regularisation and aggregation. This paper examines the consequences of the regularisation on sample variograms and proposes another procedure to integrate samples called “aggregation”. The variogram models of integrated data are compared with the theoretical punctual model. The point-support variogram presents some advantages, such as the possibility of utilizing samples without compositing their values. But, this implies to modify the classical kriging system. The ways of managing data with different supports are applied to a complex dataset of an iron ore body. The spatial variable analysis from the composited borehole samples demonstrates the impact of the integrating methods through cross validation. Results show the effect of the variogram model in the kriging system and the accuracy of the evaluation. Also evidenced are the sensitivity to the integration method, the selected parameters and the benefits of the theoretical punctual variogram.

The paper presents the evaluation of quarrying operations as specified by the Eco-Label standards for hard coverings, while it develops the work done by (Elkarmoty et al., 2020a). The economic and environmental optimization of the quarry activities were analysed taking in to account several parameters: production costs, obtainable revenues, waste production, dust and CO2 emissions, water and energy consumption, and the Eco-Label ‘natural resource’ criteria for hard coverings. For the dust and CO2 emissions, water and energy consumption, the research presents a comparison between a chain saw cutter machine and a diamond wire cutter machine. The research’s objective is to evaluate the optimal sustainable engineering and optimization practice in terms of economy and the environment by means of block dimensions and block cutting machinery choices. The research was implemented in a case study of limestone quarry bench in Italy. The highest obtainable recovery ratio was detected as 53%, while the obtainable revenues were found in correlation with the recovery ratio, decreasing with increasing block surface area. However, the lowest production costs were obtained for the block dimension that reflected the lowest recovery ratio, hence, highest waste volume. The dust emissions, energy consumption and carbon footprint of the block cutting operations of the quarry were lower when the diamond wire cutter was used, compared to the chain saw cutter, respectively. For the block cutting of the bench, using blocks with lower surface area were found to have higher recovery ratios than the threshold value which Eco-Label natural resources criteria indicates. The excellence level of the Eco-Label criteria can be obtained in the presented case study only by one block dimension. Each criterion was evaluated in order to find the best practice for the quarry in terms of environment, economy and sustainability.

A crucial aspect of geothermal reservoir engineering is the performance and interpretation of field tests, such as production tests, flowing temperature and pressure logs - both during injection and production, and down-hole pressure transient recording. Such tests are of great importance in order to evaluate the reservoir properties and to predict wells production capacity. However, production tests duration is often limited by environmental constraints related to the disposal of brines, and the running of downhole measurements is constrained by safety and cost considerations related to the use of expensive tools in high temperature high productive wells. From this point of view, the capability to simulate the whole production tests can be extremely useful to improve the data interpretation and reduce the impact of lacking field data. In particular, the coupled simulation of transient fluid flow within the wellbore and the reservoir with the matching of output production curve, flowing logs, and downhole pressure transients, should result in a more reliable evaluation of reservoir properties. This can be done using T2Well, a coupled wellbore-reservoir numerical simulator, with proper equation of state (EOS) modules. EWASG is an EOS module for high enthalpy geothermal fluids consisting of mixtures of water, salts and a non-condensable gas (NCG). We have recently plugged it into T2Well and also improved the analytical computation of heat exchange between the well and the surrounding formations at early time, which may be important for reproducing the transient results of production tests. The resulted wellbore-reservoir simulator, T2Well-EWASG, is capable to simulate high enthalpy geothermal wells. We validated T2Well-EWASG against flowing pressure and temperature logs taken from published literature.

In multi-unit deposits, the risk of facing uncertainties in estimating geological domains is generally high. The uncertainties increase when there is no exact boundary among geological domains, which is called “soft boundaries”. The geostatistical method of Partial Grade (PG) is an estimation technique developed for multi-unit deposits in the presence of “soft boundaries” when the spatial variability of the grades varies between different geological formations. A partial grade is the product of the indicators of the geological domains with the ore grade, so the partial grade cokriging of different geological formations can be performed in the case of multi-unit deposits. However, the partial grade cokriging is relevant only in the presence of a “border effect”, evidencing the evolution rate of average grade when moving from one geological domain to another. Additional geostatistical tools with respect to standard geostatistics, such as variogram ratio and preferential relationship schemes allows to identify the grade relation among different geological domains. In this work, we present an application of partial grade cokriging to an iron multi-unit deposit with soft boundaries located in Iran. Up to the knowledge of authors, although the PG method has been applied to several case studies in literature, this application is the first case study where the border effect is present. The three main geological domains are defined: Poor mineralization: (low grade of iron, 20 < Fe% < 45), Rich mineralization: (high grade of iron, Fe%≥ 45) and Metasomatite mineralization (strongly altered rock, Fe% < 45). The partial grade cokriging results have shown to reduce uncertainties in grade estimation of geological domains with respect to the classical geostatistical estimation methods (Ordinary Kriging and Co-Kriging). Results were validated with the blast hole data used as reference.

Površinske temperature i hidrogeološki uvjeti ključni su parametri u mnogim inženjerskim primjenama poput izgradnje podruma i drugih podzemnih prostorija te kod procjene plitkoga geotermalnog potencijala. Međutim, teško je otkriti prirodne, tj. izvorne, toplinske uvjete, poglavito u plitkim, podzemnim, gradskim područjima. Razlog tomu je ljudski utjecaj. Stoga procjena toplinskih varijabli u takvim uvjetima postaje sve važnija, jer raste i uporaba geotermalne energije, posebice kao obnovljivoga izvora. Cilj rada bio je prikazati trodimenzionalni model takvih uvjeta, kalibriran eksperimen-talnim podatcima. Tako je opisano ponašanje topline u podzemlju pod utjecajem građevina u odabranome seoskom području Italije. Temperaturne varijacije u prostoru i vremenu ovisile su o površinskim stijenama (i/ili tlu), klimi i svojstvima same građevine. Svi ti parametri razmatrani su unutar modela sezonskih promjena temperatura. Rezultati modela u područjima niske urbanizacije neizravno upućuju kako promatrani parametri imaju veliku važnost u visoko urbaniziranim područjima. Nadalje takvi rezultati mogu se uključiti u buduće modele plitkoga podzemlja i razmjenji-vača topline te unaprijediti kako njih, tako i opću uporabu geotermalne energije. Ground temperature and hydrogeological conditions are key parameters for many engineering applications, such as the design of building basements and underground spaces and the assessment of shallow geothermal energy potential. Especially in urban areas, in the very shallow depths, it is difficult to find natural undisturbed underground thermal conditions because of anthropic interventions. The assessment of underground behaviour in disturbed conditions will become more and more relevant because of increasing awareness to energy efficiency and renewable energy topics. The purpose of this paper is to show a three-dimensional representation - based on models calibrated on experimental data - of the underground thermal behaviour affected by a building in a rural area in Italy. Temperature varies in space and time and it depends on ground, climate and building characteristics, and all these parameters are taken into account by the seasonal periodic modelling implemented. The results obtained in a context of low urbanization indirectly suggest the importance of these effects in dense urban areas; taking greater account of these aspects could lead to improvements in the design of underground spaces and geo-exchanger fields for geothermal energy exploitation.

In mineral resource estimation, identification of the geological domains to be used for modeling, and the type of boundaries dividing them, is a major concern. Generally, the variables within a domain are estimated with an assumption of the hard boundaries (sharp contact). However, in many cases, the geologic structures that generate a deposit are transitional (overlapping of several geologic domains). Consequently, boundary identification of the geological domains is essential for an accurate estimate of resources. This paper considers a real application to examine whether the addition of geologic information benefits grade estimation in the presence of transitional boundaries. Results proved that the accuracy of the grade estimation can be improved by adding geological information and there is a significant sensitivity in grade estimation results in the existence of transitional boundaries.

Railways and roads frequently cross natural corridors like alluvial plains and alpine valleys. Here, structures and infrastructures can be affected by natural hazards such as floods and landslides. In some cases, the design has disregarded the possible interactions between slope processes and linear infrastructures. This work summarizes a 20-year long research comprising monitoring and laboratory data, field investigations and numerical modelling about an active 25-million m3 rock block slide threatening the serviceability of a highway tunnel in the Eastern Italian Alps, along the Tagliamento River Valley. The effectiveness of 3D geotechnical and hydrogeological numerical modelling calibrated on long-term monitoring datasets in planning countermeasures for landslide risk mitigation is demonstrated. A correlation between rapid snowmelt and/or extreme rainfall events and landslide activity is found. Moreover, monitored stream and spring discharges, together with seepage along the tunnel, appear to be strictly related to the displacements measured by GNSS and in-place inclinometers. In particular, the landslide accelerates once the threshold of 20 l/s in the tunnel seepage discharge is overcome. The continuous monitoring of specific electrical conductivity in five points allows tunnel discharge to be characterized identifying two type of groundwater circulation, one deeper and one perched, developing during extreme event. These facts clarify the role played by rainfall infiltration and groundwater flow in the fractured rock mass in promoting slope movements and damage in the tunnel lining. Based on these observations, two different 3D codes are used for groundwater flow simulation (FEFLOW by DHI-WASY) and stress and strain analysis (FLAC3D by ITASCA). The actual conditions of the slope and the possible countermeasures have been simulated. In FEFLOW, the Equivalent Porous Medium (EPM) approach is adopted with a model domain of 8-km2 including the landslide and the infrastructures. In FLAC3D, the properties of the sliding surface are reduced to simulate the wetting caused by the rising of hydraulic head in the fractured rock mass during the snowmelt or rainfall events. The 300-m long extension of an already existing T-shape drainage tunnel is analyzed. The simulated countermeasure work induces a lowering of the hydraulic head in the rock mass; consequently the reduced geotechnical properties have to be applied to a smaller section of the slip surface, resulting in a decrease of displacements. Even though the stabilizing effect is not definitive, mainly because of the volume of the unstable slope, the extension of the drainage tunnel reduces both the intensity and the duration of the water seepage into the tunnel with direct benefits for the tunnel serviceability.

Il georadar o GPR (Ground Penetrating Radar) può essere utilizzato per rilevare la presenza di fratture nei depositi di rocce ornamentali con delle limitazioni in termini di profondità di penetrazione e risoluzione dei risultati. Il GPR è stato scelto in questo lavoro di ricerca per l’utilizzo in cava in quanto è in grado di fornire un’immagine del sottosuolo, attraverso l’ammasso roccioso sia in 2D che in 3D. Ciò consente di definire lo stato reale di fratturazione che, a sua volta, permette una modellazione dei fenomeni di frattura secondo un approccio deterministico 3D. Questo si rivela utile per la valutazione dei giacimenti lapidei e necessario per l’ottimizzazione della produzione e la minimizzazione degli scarti. Il GPR potrebbe essere utilizzato non solo a livello di bancata in cava, ma anche per l’analisi dei blocchi. Di conseguenza, l’ottimizzazione della produzione può avvenire in modo sostenibile per entrambe le applicazioni.

TMGAS, an equation of state module of TOUGH2 V.2.0 reservoir simulator, was used to model the migration of CO2, H2S, and CH4 in a deep sedimentary formation. The scope is the improvement of the description of non-condensable gas (NCG) migration within modeling studies of sedimentary basins’ evolution. Different scenarios have been simulated with NCG migration taking place in a large sedimentary formation discretized with a full 3D Voronoi approach by using specifically improved versions of the pre- and post-processing tools for TOUGH2 developed at the University of Bologna. Simulated reference scenarios are related to the migration of CO2, H2S, and CH4 generated at constant rate for 1 × 106 years in a fresh water aquifer. Additional scenarios are simulated with NCG migration taking place in the same formation but saturated with brine. The effects of pressure-temperature-composition (PTX) conditions on thermodynamic equilibria, phase composition, phase thermo-physical properties and, consequently, on the migration features of different NCGs are modeled and discussed. © 2016 Society of Chemical Industry and John Wiley & Sons, Ltd

The software TOUGH2Viewer 2.0, originally available since 2012, is an enhanced visualization software specifically designed to visualize the results of TOUGH simulations performed using structured and fully unstructured 3D Voronoi grids. 3D Voronoi grids permit a great degree of flexibility when accurate numerical simulations are required. The TOUGH family of simulators represents a set of software well-known worldwide for numerical modeling and simulation for coupled transport of water, vapor, non-condensable gas and heat in porous and fractured media. Nevertheless, TOUGH has no native enhanced pre- and post-processing tools, and several pre- and post-processing tools have been developed. Using TOUGH2Viewer the users can interactively navigate the model, a 3-dimensional virtual environment, by means of a Graphical User Interface (GUI). This new version of TOUGH2viewer allows the editing of numerical models by dedicated GUIs, adding pre-processing capabilities.

The exploitation potential of shallow geothermal energy is usually defined in terms of site-specific ground thermal characteristics. While true, this assumption limits the complexity of the analysis, since feasibility studies involve many other components that must be taken into account when calculating the effective market viability of a geothermal technology or the economic value of a shallow geothermal project. In addition, the results of a feasibility study are not simply the sum of the various factors since some components may be conflicting while others will be of a qualitative nature only. Different approaches are therefore needed to evaluate the suitability of an area for shallow geothermal installation. This paper introduces a new GIS platform-based multicriteria decision analysis method aimed at comparing as many different shallow geothermal relevant factors as possible. Using the Analytic Hierarchic Process Tool, a geolocalized Suitability Index was obtained for a specific technological case: the integrated technologies developed within the GEOTeCH Project. A suitability map for the technologies in question was drawn up for Europe.

Discontinuities can be hidden or out-cropping with variable aperture sizes in rock media. Obtaining deterministic geo-spatial features of discontinuities inside quarried ornamental stone blocks is a decision-making tool for the post processing phase of cutting slabs. In a case study of a limestone block, discontinuities were detected by the Ground Penetrating Radar (GPR) through a high frequency antenna (700 MHz) and deterministically modeled in three dimensions following the method presented in Elkarmoty et al. (2017). The use of the 700 MHz GPR antenna in this kind of rock allowed to detect tiny-size apertures of discontinuities. The results showed that it is possible to detect and model not only the outcropping discontinuities, but also the hidden ones. Hidden three-dimensional voids or defects were detected and modeled as well. The resulting model was visualized in different orientations, using a 3D data visualization software package, for a better perception of the results.

none 5 no The paper examines methods of assessing the critical fractures and quality of an ornamental stone deposit. Fracture status was evaluated by an in-situ Ground Penetrating Radar (GPR) test. The resulting 3D GPR model allowed exploration of the extension, shape, and orientation of the detected fractures surfaces. It also identified a rock stratum with a noticeably lower load of critical fractures compared to the other strata. Physico-mechanical properties were investigated by laboratory tests allowing classification of the deposit into quality categories, which provided a promising correlation with the GPR survey results. mixed Elkarmoty, Mohamed; Colla, Camilla; Gabrielli, Elena; Bonduà, Stefano; Bruno, Roberto Elkarmoty, Mohamed; Colla, Camilla; Gabrielli, Elena; Bonduà, Stefano; Bruno, Roberto

TOUGH2 is an integral finite differences numerical simulator for non-isothermal multiphase flow in fractured porous media, which can manage complex spatial discretizations. Numerical simulation accuracy is affected, among other things, by grid resolution. Increasing the grid resolution requires computational and operating costs depending on the number of nodes and variables processed. The complexity of the management of the model increases when unstructured grids and local refinement are used. In order to improve the management and optimize the activities to update the model, an open source pre-processor has been developed using the open source codes GRASS GIS, SQLite and AMESH. Operations such as domain discretization, rock type assignment and mesh file generation have been automatized. Graphical interfaces allow for a user-friendly utilization. Operating errors and time required by pre-processing activities to generate and update locally refined unstructured grids have been reduced. Productivity in numerical modeling has been substantially increased. A novel approach to generate TOUGH2 input file through GIS is presented.TOUGH2GIS automatically creates locally refined unstructured 3D grids.Rock types attribution to grid blocks is automatically and efficiently performed.Seamless integration into an available open-source GIS package.An application to a sample dataset shows method feasibility.

This study is part of a wider feasibility analysis of a new forestry road in the Dolomitic region. The investigated area is located in northeastern Italy, in the Carnic Alps complex geological context. The rock mass which would be crossed by the tunnel is a highly tectonized limestone characterized by a relatively high strength of the intact rock. The project focuses on the rock mass characterization and the modelling of its behavior by means of numerical simulations with a Finite Elements (FE) code. The generalized Hoek-Brown criterion is used, normal and shear stiffness of the joints are evaluated and different strategies for the representation of the rock mass discontinuities are adopted. The effects of two support systems, preliminary designed by a diffused simplified method, are evaluated focusing on the space around the tunnel, where the joints reach the critical state.

How to estimate the risk of the occurrence of non-hydrocarbon components (nonHC) such as carbon dioxide (CO2), hydrogen sulfide (H2S) or nitrogen (N2), is one of the main issues in the field of petroleum exploration. Numerical models can provide valuable tools to predict the occurrence and distribution of such components. Different approaches exists to this end, starting from the simplest ones, relying onto geometrical considerations, up to those based on a fully physical description of the migration and accumulation processes.In this work, a procedure for efficient coupling of petroleum system analysis withmultiphase Darcy flow simulations is developed to obtain 3D time dependent representation of the migration paths and accumulation volumes of nonHC at basin scale on a geological timescale. We focus on the tests carried out to prove that is technically feasible to run simulations of very deep geological formations (high P, T, salinity) even if considering a very detailed picture of the transport phenomena (buoyant, viscous and capillary forces). The challenge is to find the right compromise between the needs to honor fine-scale hydrostratigraphic details of the structure and the size of the numerical model in its discretized form.

Blended cements are largely used for concrete: they are usually considered cements with a low environmental impact, as they require less clinker than ordinary Portland cement (OPC). Different constituents can be used as supplementary clinker component usually leading to cement with high resistance to outdoor environment. Polishing residue (PR), coming from porcelain stoneware tiles production, can be successfully used as new constituent for blended cement, however its action for enhancing the durability of cement matrix must be assessed. With this purpose, electrochemical tests (half cell potential, impressed voltage and linear polarization techniques) have been carried out on steel reinforced mortar samples, prepared using a 25% PR based cement and 100% OPC as binder and exposed to a 3.5% NaCl solution. The corrosion resistance results and microstructure analysis highlight better durability performances for PR based cement than those exhibited by OPC, mainly for curing time > 28 days.

Rock mass fractures adversely affect the cutting of commercial-size blocks and cause rock material loss in ornamental stone quarries. In order to obtain a reliable evaluation and an optimized production of ornamental stone deposits, it is fundamental to detect fractures in a non-destructive manner identifying them through 3D deterministic modeling. In this study, a recently published fracture modeling strategy, based on Ground Penetrating Radar (GPR) survey was implemented on a large area of bench (27.0 m &times, 65.0 m) in a limestone quarry in Italy. The survey was done using a dual-frequency GPR system (250 MHz and 700 MHz). The objective of this work was to investigate the large-scale applicability of the mentioned fracture model for future consideration in quarrying optimization studies. Only the 700 MHz radargrams were considered for the fracture modeling, as they provided a higher resolution than the 250 MHz radargrams and a penetration depth of about 4.0 m. The bulk dielectric constant of the rock mass of the bench was estimated by averaging the velocities obtained from fitting the hyperbolic diffractions of fractures at different depths. The model showed that fractures from the same family set can have noticeable spatial variations. The results allowed us to roughly estimate the sizes of the blocks exploitable from the different rock layers of the quarry bench.

none 5 no Rock mass fractures adversely affect the production of ornamental stone quarries. Fractures cause natural rock blocks which threaten extracting the required commercial block size of ornamental stones. An accurate subsurface detection and modeling of fractures is required for pre-exploitation evaluation and planning. This paper introduces a new three-dimensional deterministic fractures modeling approach using Ground Penetrating Radar (GPR) as a data acquisition tool. A case study was performed in a fractured bench of a sandstone quarry in Firenzuola, Italy, using a 400 MHz GPR antenna. To accurately detect fractures at true depth, an in-situ calibration based on knowing the depth of a subsurface reflector, as a reference, allowed to estimate a bulk dielectric constant of the rock mass in the time of data acquisition. A data interpretation tracing technique was developed to model fractures as 3D surfaces in two forms, either irregular or planes. The modeled fractures were visualized through a multiplatform visualization software package (ParaView). A comparison between the orientations of the fractures measured through the traditional manual survey and the orientations of the modeled fractures is presented as a possible geologic validation for the detection and interpretation of fractures. For the objective of pre-exploitation evaluation, a distribution analysis study of fractures allowed to obtain an evaluation-based fracture index for the bench of the case study. mixed Elkarmoty, Mohamed; Colla, Camilla; Gabrielli, Elena; Bonduà, Stefano; Bruno, Roberto Elkarmoty, Mohamed; Colla, Camilla; Gabrielli, Elena; Bonduà, Stefano; Bruno, Roberto

Within the MAC-GEO research project, funded by Regione Toscana and addressed to the exploitation of high enthalpy geothermal systems, the authors worked on the utilization and customization of the open source numerical simulator TOUGH2, as implemented in the code dedicated to model calibration iTOUGH2. TOUGH2 is one of the most used numerical simulation software for non-isothermal flow of multicomponent, multiphase fluids in one, two and three-dimensional porous and fractured media. Lacking an official Graphical User Interface tool for post-processing operations, several commercial and academic software have been developed to manage and display TOUGH2 input and output data files. Almost all of these tools seem to have limits to visualizing parameter values of the numerical model, work only with a predefined binary version of TOUGH2, and only a few of them can manage locally refined unstructured grids (i.e. Voronoi grids). To overcome these limitations, the authors have developed and tested a dedicated software application (called TOUGH2Viewer) for reading and managing TOUGH2 output files, written in Java and able to provide an interactive 3D view of the numerical model. Several functionalities have been implemented for block query and searching, contour mapping and 3D surface mapping of TOUGH2 primary variables (i.e. pressure, temperature, etc.). TOUGH2Viewer is also able to display 2D and 3D views of mass and heat flow between blocks, for each time step in which the simulation proceeds. The application described in this paper is under development to improve its functionalities; nevertheless the current software release is a valid support tool for post-processing that significantly improves the possibility to inspect the simulated data coming from TOUGH2.

Croatian. Plitka, potpovršinska, temperatura (na dubinama plićim od 50 m) nije konstatna, niti u prostoru, niti vremenu. Takve promjene posljedica su utjecaja toplinskih „pulseva” različitoga podrijetla poput Sunčeva, geotermalnoga ili ljudskoga. Točna procjena temperature ključni je čimbenik kod planiranja energetskih sustava temeljenih na plitkoj geotermalnoj energiji. U takvim projektima, temeljenim na izmjenjivačima topline u plitkim bušotinama, potpovršinska je temperatura promjenjivija, što utječe na iznos pridobivanja topline, tj. utiskivanja fluida. Praćenje takvih promjena važno je stoga kod svih projekata toplinskih izmjenjivača vezanih uz plitka geotermalna ležišta. U radu je prikazan praktičan oblik toga, ali i glavni problemi koje je moguće susresti tijekom instaliranja, testiranja ili uporabe potrebne geotermalne opreme. Dan je primjer polja u kojemu je smješteno osam koaksijalnih izmjenjivača topline, 30 metara dugačkih te povezanih s prototipom uređaja dvostruke toplinske crpke (zračne i dubinske). Ground temperature at shallow depths (< 50 m) is not stable, nor in space, neither in time, and its behaviour is the result of the superimposition of effects of heat pulses of different origin: solar, geothermal and anthropic. The correct assessment of ground temperature is a crucial point when designing a shallow geothermal energy system. In geothermal closed loop projects using short borehole heat exchangers, the ground temperature has more variability and affects the rate of heat extraction/injection. Monitoring of the ground temperature can therefore be useful in ground source heat pump projects to correctly understand the behaviour of a shallow geothermal reservoir subjected to heat extraction/injection. This paper illustrates the practical aspects and main issues occurred in the installation, testing and working phases of a monitoring system realised to record ground temperature in a geothermal application. The case study is a field of eight coaxial borehole heat exchangers, 30 m long, connected to a novel prototype of dual source (air and ground) heat pump.

The TOUGH family of multi-component, multiphase numerical reservoir simulators have a well know and a long history of applications in different fields of mass and heat transport in porous media. The use a full three-dimensional (3D) unstructured grid permits a great degree of flexibility to reproduce the geometry of complex geological formations and performs accurate reservoir numerical simulations. The full 3D Voronoi tessellation approach also allows reproducing the geometry of geological formations (useful, for example, in directional drilling). In this work, we present some applications of the 3D Voronoi pre- and post-processing software tools dedicated to the TOUGH family of codes (developed at the DICAM Department of the University of Bologna by the Geothermal research group), to study problems of gas migration in hydrocarbon reservoirs. In particular, a small set of 3D grids of a deep sedimentary formation has been created with VORO2MESH, and the simulation results analysed with TOUGH2Viewer. VORO2MESH is a software coded in C++ able to rapidly compute the 3D Voronoi tessellation for a given domain and to create a ready-to-use TOUGH2 MESH file, up to million blocks. It is based on the well-known and powerful open source voro++ library. The new extended version of the TOUGH2Viewer post-processor was used to easily inspect the 3D Voronoi discretization and to better manage the numerical simulation results. The software, written in Java, handles the visualization of both 3D grids (structured and unstructured) and simulation results. This study shows the effectiveness of these tools, and that the use of unstructured grids, instead of structured grids, substantially improve both the reproduction of the geological model and the TOUGH simulation results.

The document is an extended abstract presented at "GeoENV 2016", the 11th International Conference on Geostatistics for Environmental Application Conference, 6-8 July 2016, Lisbon, Portugal.