Dissertations / Theses on the topic '3D geological model'

The town of San Leo, situated in the Northern Apennines in Italy, is subject to instability phenomena due to its particular geological nature, described as a highly fractured calcarenite slab embedded in clay-rich terrains. The 3D geological model of the San Leo plateau, comprehending the eastern zone of the rock slab, was developed through the integration of data obtained from laser scanning and photogrammetrical surveys, as well as surface and core drilling geomechanical surveys, into one single system that enables the visualization of all structural features of the plateau in association with one another, including superficial and in-depth fractures and the equipment from the monitoring system that surveils the rock mass behavior. In that manner, it was established that the area along the northeastern scarp formed by the 2014 landslide event is highly fractured, characterized by an extremely high number of closed and few open fractures, whereas the area surrounding the road to the San Leo fortress along the eastern cliffs present fewer fractures in general, located predominantly in the vicinity of the eastern lateral walls. Moreover, two possible collapse scenarios were evaluated in the northeastern cliffs, in which the failure mechanism corresponding to the 2014 event was emulated for fractures parallel to the scarp, resulting in the collapse of a rock volume equivalent to 428,913.804m3. The persistence and behavior of the fractures involved in these scenarios were also analyzed, indicating that such events are not imminent at the present time.

With the advancements in acquisition and processing of seismic reflection data recorded over crystalline rocks, building three-dimensional geologic models becomes increasingly favorable. Because of little available petrophysical data, interpretations of seismic reflection data in hardrock terrains are often speculative. Potential field data modeling are sometimes performed in order to reduce the ambiguity of seismic reflection interpretations. The Kristineberg mining area in the western part of the Paleoproterozoic Skellefte Ore District was chosen to construct a pilot three-dimensional geologic model in an attempt to understand the crustal architecture in the region and how the major mineral systems operated in this architecture. To contribute to this aim, two parallel seismic reflection profiles were acquired in 2003 and processed to 20 sec with special attention to the top 4 sec of data. Several reflections were imaged and interpreted by the aid of reflector modeling, borehole data, 2.5D and 3D potential field modeling, and geological observations. Interpretations are informative at the crustal scale and help to construct a three-dimensional geologic model of the Kristineberg mining area. The three-dimensional geologic model covers an area of 30×30 km² down to a depth of 12 km. The integrations help to interpret a structural basement to the Skellefte volcanic rocks, possibly with Bothnian Basin metasedimentary affinity. The contact is a shear-zone that separates the two units, generating large fold structures, which can be observed in the region. The interpretations help to divide the Revsund granitic rocks into two major groups based on their present shape and thickness. A large gravity low in the south is best represented by the intrusion of thick dome of Revsund granite. In the north, the low-gravity corresponds to the intrusion of sheet-like Revsund granites. In general, the structure associated with the Skellefte volcanics and the overlying metasedimentary rocks are two thrusts exposing the Skellefte volcanic rocks in the cores of hanging wall anticlinal structures. Lack of coherent reflectivity in the seismic reflection data may be due to complex faulting and folding systems observed in the Skellefte volcanics. Ultramafic sills within the metasedimentary rocks are interpreted to extend down to depths of about 5-6 km. The interpretations are helpful for targeting new VHMS deposits and areas with gold potential. For VHMS deposits, these are situated in the southern limb of a local synformal structure south of the Kristineberg mine, on the contact between the Revsund granite and the Skellefte volcanic rocks. A combination of metasedimentary and mafic-ultramafic rocks are highly gold prospective in the west, similar to observations elsewhere in the region. There are still questions that remain unanswered and need more work. New data in the study area will help to answer questions related to e.g., an enigmatic diffraction seismic signal in Profile 5 and the structural relationship between the Skellefte volcanic rocks and the Malå volcanics. Although the derived 3D geologic model is preliminary and constructed at the crustal scale, it provides useful information to better understand the tectonic evolution of the Kristineberg mining area.

The city of Wellington has a high population concentration and lies within a geologically active landscape at the southern end of the North Island, New Zealand. Wellington has a high seismic risk due to its close proximity to several major fault systems, with the active Wellington Fault located in the north-western central city. Varying soil depth and properties in combination with the close proximity of active faults mean that in a large earthquake rupture event, ground shaking amplification is expected to occur in Thorndon, Te Aro and around the waterfront. This thesis focuses on the area bounded by Thorndon Overbridge in the north, Wellington Hospital in the south, Kelburn in the west, and Oriental Bay in the east. It includes many of the major buildings and infrastructural elements located within the central Wellington commercial area. The main objectives were to create an electronic database which allows for convenient access to all available data within the study area, to create a 3D geological model based upon this data, and to define areas of different seismic subsoil class and depth to rock within the study area at a scale that is useful for preliminary geotechnical analysis (1:5,000. Borelogs from 1025 holes with accompanying geological and geotechnical data obtained from GNS Science and Tonkin & Taylor were compiled into a database, together with the results from SPAC microtremor testing at 12 sites undertaken specifically for this study. This thesis discusses relevant background work and defines the local Wellington geology. A 3D geological model of the central Wellington commercial area, along with ten ArcGIS maps including surficial, depth to bedrock, site period, Vs30, ground shaking amplification hazard and site class (NZS 1170.5:2004) maps were created. These outputs show that a significant ground shaking amplification risk is posed on the city, with the waterfront, Te Aro and Thorndon areas most at risk.

Object of this work is the 3-D modelling of complex geological architectures in the Quaternary Po Basin (Lombardy, Italy). Reliable surface and subsurface models in Quaternary alluvial basins are important for several applications, including groundwater research and management, geohazard evaluation, exploitation and protection of other natural resources. The study area is the Po Plain-Apennine border in Lombardy (Italy), in a peculiar sector where the structural culminations of the buried Emilian Arc salient of the Northern Apennines determine the location of isolated reliefs in the Po Plain (i.e. San Colombano Hill and Casalpusterlengo – Zorlesco subtle relic reliefs). This area was selected because it permits to improve the 3-D modelling procedure in a complex tectono-stratigraphic-geomorphological setting, which is of interest for both the still controversial geological reconstructions of the Po Basin and the relevant issues in groundwater management and geothermal energy exploitation. The Quaternary sedimentary fill of the southern margin of the Po Basin in Lombardy records the complex interplay between active Apennine thrusting to the South, rebound and isostatic response to deglaciations at the flexed Alpine margin to the North and the dynamics induced by Quaternary glacial cycles. All of these factors produced the assemblage of nested stratigraphic, structural and geomorphological complexities which are the object of this work. Reliable 3-D models must account for multiple ranks and scales of sedimentary heterogeneity. To obtain such a result, this works attempts to compute 3-D models, constrained not only by the traditional explicit geological “hard” surface and subsurface data, but also by the implicit “soft” data represented by the increments of the geological evolution of the basin. At present, none of the available modelling methods incorporates geological evolution, hierarchy of stratigraphic and structural components of geological heterogeneity and uncertainty as formal rules of 3-D model building in a straightforward manner. Aim of the work is to propose an integrated, multidisciplinary methodology to combine both explicit and implicit geological knowledge as constraint for 3-D (4-D) architectural geological modelling of the study area. Specific aims of this work are: i) to reconstruct the surface and subsurface Quaternary geology of the study area at different scales; ii) derive the increments and the autogenic vs. allogenic controlling factors on the geological evolution; iii) develop alternative 3-D (4-D) models of the Quaternary sedimentary infill of the area, honoring the new maps and subsurface reconstructions and accounting for the incremental geological evolution; iv) contribute to improve and implement a method that combines explicit geological data with the implicit hierarchic and evolutionary constraints for 3-D geological modelling. A multidisciplinary methodology has been set-up. It integrates i) classical geological, sedimentological, stratigraphic, geopedological, geomorphological and structural field surveys; ii) subsurface reconstruction based on stratigraphic correlation of borehole logs and geophysical images, along a fence of 2-D cross-sections over an area of 400 km2 and a maximum investigation depth of 150 m b.g.s.; iii) 3-D geological modelling based on integration of the GIS management of the multiple data-sets and the GeoModeller® 3-D modelling software. GeoModeller® was chosen for the feasibility to deal with the bounding surfaces, which is the key-concept to describe hierarchic frameworks and the key to introduce the genetic interpretation of the basin history (4th dimension) into 3-D representations. To do that, new software routines and novel concepts for the modelling rules were set-up and implemented in the commercial code. Results of the work include: i) a new geological and geomorphological map of the San Colombano hill at 1:10.000 scale over an area of about 60 km2; ii) a hierarchic stratigraphic scheme of the surface-subsurface Quaternary succession of the southern Po Basin, integrated to the iii) incremental tectono-depositional evolution of the Po Basin-Apennine border, that relates the ranking and the significance of the stratigraphic and morphological boundaries to the hierarchy of the Quaternary increments of the geological evolution; iv) the conceptualization of the implicit hierarchic rules to be introduced into 3-D model building, and the procedure to progressively include the explicit and implicit geological rules within multi-scale realizations; v) some new computing routines which let GeoModeller® to manage the new rules and vi) alternative 4-D geological models accounting for different interpretations of the geological evolution. Six high-rank increments of the geological evolution (“stages”) punctuated by low-rank steps have been described in this work. During stages 1 and 2, N-ward thrusting along the blind Emilian Arc originated the Zanclean and the Gelasian Unconformities. On the San Colombano hill, the Calabrian shallow marine San Colombano Fm. (PL4 highest-rank succession) unconformably overlies the truncated deep-marine Miocene formations, up-thrusted during Mio-Pliocene. At stage 3, Early to Middle Pleistocene increments of thrust-folding at the northernmost buried reaches of the Emilian Arc induced erosion of the intra-Calabrian unconformity (U1) and separated local depocentres related to the San Colombano and Casalpusterlengo – Zorlesco structures. These were filled by transitional and alluvial units (PS1 highest–rank succession). These regressive deposits, lap onto the uplifting structures of San Colombano and Casalpusterlengo - Zorlesco, suggesting the onset of their structural separation. At stage 4, these latter two structures were separated from the San Colombano thrust, since the Middle Pleistocene, by means of a newly interpreted dextral lateral ramp (San Colombano lateral ramp), as testified by the delayed migration of the depocentres of the Middle Pleistocene glacio-fluvial units and by the time-shift of the onlaps onto the different structures. After folding of U1, at the base of these units, the Early-Middle Pleistocene unconformity U2 was carved, bounding the base of the PS2 alluvial and glacio-fluvial high-rank succession. During stage 5, Late Pleistocene alluvial and glacio-fluvial units (PS3 highest-rank succession, correlative to late Besnate and Cantù Alpine glaciations) covered, through the Late Pleistocene unconformity (U3), the older glacio-fluvial succession in the subsurface of Casalpusterlengo and Zorlesco areas, while they terraced the deformed marine succession in the San Colombano area, both on the uplifted hilltop and on the surrounding “Plain Main Level” (Castiglioni and Pellegrini, 2001). Syndepositional normal faulting, related to dextral wrenching regime, occurred during this stage. Fault-related offset of Late Pleistocene units, stratigraphic and morpho- structural evidences (facets, relic surfaces and drainage patterns), document ongoing transtension, at stage 6 (Latest Pleistocene – Holocene; U4 unconformity), plausibly relating to the NNW-wards thrusting and related wrenching along the Pavia-Casteggio lateral ramp (Benedetti et al., 2003). Field evidences suggest to propose a link between the entrenchment and the anomalies of the post-glacial river network at the southern margin of the Po Plain to this tectonic stage. This reconstruction links the origin of the highest-rank unconformable stratigraphic boundaries to the Quaternary tectonic stages of Apennine thrusting, wrenching and extension. The intermediate- and low-rank unconformities relate to both minor tectonic increments and to the climatic-driven glacial cycles, because the bases of the glacio-fluvial units are nested within the highest-rank tectonic-induced unconformities. On the isolated reliefs, in situ paleosols testify the preservation of non-erosional surfaces, i.e. morphological surfaces, related to sites of morphological stability. These became the sites for loess aggradation during the Late Pleistocene, that means when the isolated reliefs had been already uplifted and the main controlling factor on deposition was climatic. The recognition of unconformable stratigraphic boundaries vs. conformable “morphological” boundaries permits to unravel the different chronostratigraphic significance of these two surface types (respectively time-transgressive and almost isochronous) and to use them to constrain the reconstruction of the chronological evolution of the basin and the 4-D model to be computed. A novel approach in the use of GeoModeller® is proposed by implementing a model building procedure based on coded ‘hierarchic rules’, at present not encompassed in the modelling suite. A rigorous routine is proposed to apply these rules to obtain at least three ranks of visualization of the 3-D geological architecture of the study area. The ordering of the geological units in the stratigraphic pile, combined with the set of the reference surface (top/bottom) and the nature of the interpolation for each surface (erode/onlap) conceptualized the hierarchic rules valid to represent complex stratigraphic architectures at each scale. 1) The isopotentials of GeoModeller® (i.e. the lowest rank surfaces which can be computed and represented by this software) describe well the morphological surfaces, i.e. surfaces stable through time. Using the orientation of the morphological surfaces as reference top boundary for model computation means to constrain the isopotentials to the deformation history of the area. This concept strongly impacts on the 3-D model application to the simulation of internal facies, as it would be necessary to simulate the distribution of hydrostratigraphic parameters. 2) Since crossing the isopotential, the erode stratigraphic boundaries bring the significance of the time-transgressive unconformable surfaces, in accordance with the geological evolution. 3) By attributing erode nature to the high-rank surfaces, and onlap rules and reverse ordering in the stratigraphic pile to the intermediate-rank ones, the resulting 3-D model displays the high-rank surfaces as composite stratigraphic unconformities, like they have been described by the geological model, since they collect the minor increments of deformation, deposition and erosion through the geological time. As a result, the proposed 3-D models are multiscale and honour the explicit geological observations and the implicit geological evolution at each scale of observation. The intermediate-rank boundaries and sediment volumes represent the result of the intermediate-rank evolutionary increments. On larger spatial and temporal scales, they can be grouped and visualized into higher-rank boundaries (‘U’ unconformities) and volumes, related to the major tectono-depositional stages. The relationship between geological history and geometrical features, with the possibility to upscale and downscale the model according to its hierarchic configuration in view of any specific application, is one novelty of the modelling results here presented. The uncertainties derived from the interpretation of the geological evolution gave rise to two alternative geological models of the San Colombano hill area. Both honour the input explicit data and differ on the interpretation of the extent of the conjugate fault systems that involved the Late Quaternary stratigraphy. The final visualization of the 3-D, ranked stratigraphic units and surfaces highlights the basic role of consistent 4-D geological models as the best synthesis of heterogeneous and multi-scale datasets, that represent the base for several applications at different scale. The adopted approach yields a model that can be easily updated, as soon as new knowledge gets available and modified, and permits to test different hypotheses accounting for any new implicit geological constraints.

Construire un macro-modèle tridimensionnel du sous-sol à partir de coupes géologiques bidimensionnelles est un problème complexe auquel les géologues sont quotidiennement confrontés. Le modèle que nous voulons construire est un modèle B-Rep non-variété dont les régions qui représentent des entités géologiques (couches, chenaux, lentilles), sont délimitées par des surfaces triangulées. Cette thèse propose dans le cadre du projet GOCAD, une méthodologie basée sur l'intégration d'informations géologiques et topologiques permettant d'obtenir automatiquement des reconstructions 3D à partir de séries de coupes géologiques 2D parallèles. Dans un premier temps, les notions géologiques et informatiques nécessaires à la lecture de ce mémoire sont présentées : la notion de faille, la description du modèle topologique utilisé. Les problèmes à résoudre y sont également détaillés comme par exemple le calcul d'intersection entre les surfaces triangulées du modèle. Dans un second temps, la méthodologie proposée est décrite étape par étape en commençant par une méthode originale de recherche d'un réseau de failles basée sur la corrélation des rejets de failles. La méthode de reconstruction, quant a elle, repose sur l'utilisation de modèles B-Rep non-variétés 2D construits à partir des structures de données mises au point par k. Weiler. Ils permettent de représenter les coupes et d'en extraire le maximum d'informations topologiques. Ils permettent également de générer les surfaces en construisant pour chacune d'elles un squelette support de la triangulation. Enfin, plusieurs reconstructions basées sur des jeux de données réels ainsi que quelques applications sont présentées avant de conclure sur les perspectives de recherche futures.

In this thesis, realistic 3D geological models of flood basalt provinces are constructed. These models are based on outcrop observations and remote sensing data from the North Atlantic Igneous Province, collected by a variety of methods including terrestrial laser scanning. Geophysical data are added to the models to make them suitable for generating synthetic seismic data. Flood basalt provinces contain a number of different volcanic facies, distinguished by their outcrop appearance and physical properties. These include tabular-classic and compound-braided lava flows, intrusions and hyaloclastites. 3D models are constructed for tabular-classic lava flows based on satellite data from Iceland and laser scanning data from a variety of locations. Models for compound-braided lava flows are based on terrestrial laser scanning data and field observations from the Faroe Islands and the Isle of Skye. An additional finding of this work is that volcanic facies can be differentiated in wireline log data from boreholes. Facies show characteristic velocity distributions which can be linked to onshore observations and used to understand volcanic facies in offshore boreholes. Data from boreholes on the Faroe Islands are used to add seismic velocities to the 3D geological models above. This thesis also develops methods and workflows for constructing 3D geological models of flood basalt lava flows. The collection of digital 3D data using terrestrial laser scanning is evaluated, and data processing workflows are developed.

Tenerife es una isla volcánica cuya superficie muestra evidencias de grandes deslizamientos y una depresión central (caldera de Las Cañadas) cuyo origen ha sido bastante controvertido. Las dos hipótesis principales se basan en una serie de colapsos de caldera del complejo central y un colapso lateral del mismo edificio. Aprovechando la existencia de un gran número de perforaciones (pozos y galerías horizontales) ejecutadas para la explotación de agua dulce en la isla de Tenerife, y haciendo uso de su registro geológico, se quiere mostrar cuál de las hipótesis encaja mejor con la información del subsuelo. En primer lugar se ha utilizado el registro geológico de las perforaciones para elaborar una base de datos de la geología del subsuelo de Tenerife. Posteriormente se ha representado esta información de forma gráfica en mapas y vistas 3D. Y en tercer lugar se han elaborado los modelos geológicos. La modelización geológica se ha desarrollado principalmente para explotaciones mineras y petrolíferas, siendo su aplicación a terrenos volcánicos novedosa. Dada la particularidad que presenta Tenerife, con un registro geológico del subsuelo kilométrico, se ha aplicado el software GeoModeller2013 para cometer la modelización geológica de la isla, combinando además la geología de superficie, topografía, batimetría y datos magnetotelúricos. Los modelos teóricos construidos, basados en los datos reales observables, recogen las ideas de las dos hipótesis de generación de la caldera de Las Cañadas (caldera de colapso vertical o por deslizamiento lateral).
Tenerife offers one of the most complex but well exposed examples of active volcanic island, in which large scale destructive events have occurred during its subaerial construction, such as giant landslides. An international controversy exists about the origin of Las Cañadas depression and the valleys of Icod, La Orotava and Güímar. The main hypothesis of the Las Cañadas origin are a succession of caldera collapses and a landslide which headwall would be the southern part of Las Cañadas depression. The island has an extensive network of sub-horizontal galleries and vertical drills that are made to capture fresh water from the main aquifers. We have used the geological records from those boreholes to build a database of the subsurface’s geology. The 3D modelling tools, that were used mainly for petrological surveys are now applied to volcanology, combining geological maps, topography, bathimetry, geophysical studies and geological records from galleries and boreholes. The 3D geological models are based in the real data and the two main hypothesis about the origin of Las Cañadas. This way we want to know what of this two ideas are more viable with the actual data, or if all this information of the subsurface can conclude what is more realistic.

L'obiettivo di questo lavoro è stato quello di confrontare il movimento del sedimento costituente la duna a sud di Foce Bevano nell’arco di tre mesi invernali; realizzato tramite la ricostruzione tridimensionale della superficie da fotogrammetria aerea a bassa quota. Sono stati effettuati due rilievi fotografici (Ottobre e Dicembre, 2017) tramite UAV (Unmanned aerial vehicle) e questi sono stati confrontati con un simultaneo rilievo tramite TLS (Terrestrial Laser Scanner), si sono discussi i risultati del rilievo tramite UAV mettendo a confronto le ricostruzione dei DEM che sono stati restituiti dal programma Pix4D. Questo metodo è risultato rapido e preciso, producendo risultati con un errore medio dell’ordine del millimetro. Riferito al rilievo di ottobre i risultati registrati di errore medio in metri sui tre assi X,Y,Z sono (-0.000077, 0.00013, -0.000027), dicembre, sempre riferito ai tre assi abbiamo i seguenti valori di errore medio in metri: ( 0.000032, -0.000108, 0.000068). Dal confronto con la ricostruzione TLS vediamo come la differenza tra i due modelli sia di pochi millimetri potendo quindi affermare che queste due tecniche sono entrambe efficaci in termini di precisione. Dal confronto fra le due superfici è risultato quindi come si sia creata una zona di sostanziale equilibrio sulla spiaggia prospiciente la duna, zona dominata da dinamiche marine, con lieve accumulo nella zona meridionale. La zona interna alle Ganivelles è fondamentalmente stabile o in lieve accumulo specialmente nella parte più a sud. Il fatto che ci siano zone di accumulo è indice dell’efficacia del sistema di ripristino ganivelles adottato sul sito bevano sud.

Orientador: José Alexandre de Jesus Perinotto
Banca: Maria Gabriela Castillo Vincentelli
Banca: Lucas Veríssimo Warren
Banca: Adilson Viana Soares Junior
Resumo: A área de estudo corresponde a um campo produtor de hidrocarbonetos situado no sudoeste da Bacia de Campos a 80 km da costa. Esta região produz hidrocarbonetos de diversos níveis estratigráficos, entre eles, os carbonatos do Albiano, foco deste estudo. O alto interesse econômico dos carbonatos no setor petrolífero mundial e a complexidade da sua análise nos dados geofísicos, justifica a importância desta pesquisa na definição de um método que auxilie na caracterização da distribuição regional da propriedade da rocha reservatório, neste caso, a porosidade. Neste contexto, este trabalho objetiva a determinação da heterogeneidade lateral e vertical das propriedades das rochas reservatórios, por meio da construção de um modelo geológico 3D de porosidade dos dois principais reservatórios identificados na Formação Quissamã (Grupo Macaé). Com esta finalidade, o método incluiu seis etapas principais: análise dos perfis geofísicos e correlação de poços, interpretação sísmica, conversão tempo x profundidade, análise de atributos sísmicos, análise geoestatística e modelagem geológica por meio da aplicação de Simulação Sequencial Gaussiana. Como níveis de referência, foram interpretados os intervalos estratigráficos correspondentes à Formação Outeiro e, na Formação Quissamã, os níveis Q1 e reservatórios R1 e R2 (principais produtores do campo). Estes níveis foram definidos com base na mudança do padrão geométrico dos perfis geofísicos de raio gama (RG), densidade (RHOB) e porosidade (Nph... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: The study area is an ancient field and hydrocarbon producer, located in the southwest of the Campos Basin, in a water depth of approximately 100 m and 80 km distant from the coast. This region produces hydrocarbon from multiple stratigraphic layers, among them, there are the Albian carbonates, the focus of this research. The high economic interest in carbonates plays by the global oil industry and the complexity of their analysis in geophysical data, justifies the importance of this research to define a method, which determine the regional distribution of the property of the reservoir rock, in this case, the porosity. In this context, this study aims to determine the lateral and vertical heterogeneity of the properties of the reservoir rocks through the construction of a 3D geologic model of porosity from two main reservoirs in Quissamã formation (Macae Group). For this purpose, the method includes six major steps: analysis of well log and correlation of wells, seismic interpretation, conversion time vs. depth, analysis of seismic attributes, geostatistical analysis and geological modeling through the application of Gaussian simulation. The stratigraphic intervals such as Outeiro Formation and Quissamã Formation, which include level Q1, R1 and R2 reservoirs (main producers of the field) were interpreted as reference levels. These intervals were defined based on the change of the geometric standard of the geophysical profiles, as gamma ray (GR), density (RHOB) and porosity (Nphi). These levels are distributed in a carbonate bank with main axis in NW-SE direction, delimited by faults and its geometry. It was observed a structural high in the central portion of the field presenting high porosity values (> 21 %) that was highlighted in the resistivity maps as filled by oil in the reservoirs R1 and R2. These carbonate facies vary to the ... (Complete abstract electronic access below)
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Outra
A área de estudo corresponde a um campo produtor de hidrocarbonetos situado no sudoeste da Bacia de Campos a 80 km da costa. Esta região produz hidrocarbonetos de diversos níveis estratigráficos, entre eles, os carbonatos do Albiano, foco deste estudo. O alto interesse econômico dos carbonatos no setor petrolífero mundial e a complexidade da sua análise nos dados geofísicos, justifica a importância desta pesquisa na definição de um método que auxilie na caracterização da distribuição regional da propriedade da rocha reservatório, neste caso, a porosidade. Neste contexto, este trabalho objetiva a determinação da heterogeneidade lateral e vertical das propriedades das rochas reservatórios, por meio da construção de um modelo geológico 3D de porosidade dos dois principais reservatórios identificados na Formação Quissamã (Grupo Macaé). Com esta finalidade, o método incluiu seis etapas principais: análise dos perfis geofísicos e correlação de poços, interpretação sísmica, conversão tempo x profundidade, análise de atributos sísmicos, análise geoestatística e modelagem geológica por meio da aplicação de Simulação Sequencial Gaussiana. Como níveis de referência, foram interpretados os intervalos estratigráficos correspondentes à Formação Outeiro e, na Formação Quissamã, os níveis Q1 e reservatórios R1 e R2 (principais produtores do campo). Estes níveis foram definidos com base na mudança do padrão geométrico dos perfis geofísicos de raio gama (RG), densidade (RHOB) e porosidade (Nphi). Os intervalos estudados estão distribuídos em um alto estrutural com eixo principal de direção NW-SE delimitado por falhas e pela própria geometria do banco carbonático. Na porção central do campo, este alto estrutural apresenta valores altos de porosidade (>21%), e se destacou no mapa de resistividade como portador de hidrocarbonetos nos reservatórios R1 e R2. Estas fácies carbonáticas variam para norte e nordeste da área com valores de porosidade mais baixos (<18%), representando a diminuição da qualidade dos reservatórios para estas regiões; esta observação, aliada à influência das falhas a sudoeste e nordeste do banco, permitiu classificar a trapa destes reservatórios como estrutural-estratigráfica. O sistema de falhas predominante na área de estudo corresponde ao NW-SE, que originou estruturas do tipo rollovers e horsts com potencial reservatório. Estas falhas abateram os blocos a sudeste e sul, que foram realçados nos mapas de atributos sísmicos como portadores de alta porosidade, comprovados por gráficos de correlação com coeficiente R2>0,65. Esta análise foi utilizada para determinar o modelo geológico 3D de porosidade, gerado por Simulação Sequencial Gaussiana. O resultado consistiu em uma representação coerente, com maior grau de certeza no alto estrutural central, que possui maior quantidade de dados de poços. Apesar das áreas a sudoeste e sul não apresentarem dados de poços, o método de Simulação Sequencial Gaussiana extrapolou altos valores de porosidade em 23% das 30 realizações geradas.
The study area is an ancient field and hydrocarbon producer, located in the southwest of the Campos Basin, in a water depth of approximately 100 m and 80 km distant from the coast. This region produces hydrocarbon from multiple stratigraphic layers, among them, there are the Albian carbonates, the focus of this research. The high economic interest in carbonates plays by the global oil industry and the complexity of their analysis in geophysical data, justifies the importance of this research to define a method, which determine the regional distribution of the property of the reservoir rock, in this case, the porosity. In this context, this study aims to determine the lateral and vertical heterogeneity of the properties of the reservoir rocks through the construction of a 3D geologic model of porosity from two main reservoirs in Quissamã formation (Macae Group). For this purpose, the method includes six major steps: analysis of well log and correlation of wells, seismic interpretation, conversion time vs. depth, analysis of seismic attributes, geostatistical analysis and geological modeling through the application of Gaussian simulation. The stratigraphic intervals such as Outeiro Formation and Quissamã Formation, which include level Q1, R1 and R2 reservoirs (main producers of the field) were interpreted as reference levels. These intervals were defined based on the change of the geometric standard of the geophysical profiles, as gamma ray (GR), density (RHOB) and porosity (Nphi). These levels are distributed in a carbonate bank with main axis in NW-SE direction, delimited by faults and its geometry. It was observed a structural high in the central portion of the field presenting high porosity values (> 21 %) that was highlighted in the resistivity maps as filled by oil in the reservoirs R1 and R2. These carbonate facies vary to the north and northeast of the area with lower values representing the decline in the quality of the reservoirs for these regions; this observation combined with the influence of the faults , in the southwest and northeast of the bank, allowed to classify the trap of these reservoirs as structural-stratigraphic. The predominant fault system in the study area corresponds to the NW-SE, which formed structures like rollovers and horsts with potential of being reservoir. These faults shot down the block to the southwest and south, which were highlighted in the maps of seismic attributes as having high porosity, supported by cross plots with correlation coefficient of R2> 0.65. This analysis was used to determine the 3D geologic model of porosity, generated by Gaussian simulation, most appropriate to the context of the geological area. The result was a coherent representation with greater certainty in the central structural high that presents a higher amount of well data. Despite the southwest and south areas do not present well data, the method was efficient in interpolate high values of porosity in 23% of 30 generated realizations.
PRH 05: 6000.0082154.13.4

This thesis uses different variants of geomechanical modelling approaches to investigate stress, strain and geometry distribution and evolution through time of the Tarfaya salt basin, located on the West African coast. This work has been conducted by geomechanically simulating a sector of the Tarfaya basin containing key features such as diapirs, faults and encasing sediments using 3D and 2D static models and 2D evolutionary models. The 3D and 2D static geomechanical models of the Tarfaya basin system allowed to predict the stresses and strains at present day. Both models are based on present-day basin geometries extracted from seismic data and use a poro-elastic description for the sediments based on calibrated log data and a visco-plastic description for the salt based on values from Avery Island. The models predict a significant horizontal stress reduction in the sediments located at the top of the principal salt structure, the Sandia diapir, consistent with wellbore data. However, the 2D static geomechanical model shows broader areas affected by the stress reduction compared to the 3D model and overestimates its magnitude by less than 1.5 MPa. These results highlight the possibility of using 2D static modelling as a valid approximation to the more complex and time-consuming 3D static models. A more in-depth study of the 2D static model using sensitivity analysis yielded a series of interesting observations: (1) the salt bodies and their geometry have the strongest impact on the final model results; (2) the elastic properties of the sediments do not impact the model results. In other words, the correct definition of the sediments with the highest material contrasts such as salt should be a priority when building static models. Such definition should be ranked ahead of the precise determination of the rheologic parameters for the sediments present in the basin. In this thesis, we also present the results of introducing an evolutionary geomechanical modelling approach to the Tarfaya basin. This study incorporates information of burial history, sea floor geometry and tectonic loads from a sequential kinematic restoration model to geologically constrain the 2D evolutionary geomechanical model. The sediments in the model follow a poro-elastoplastic description and the salt follows a visco-plastic description. The 2D evolutionary model predicts a similar Sandia diapir evolution when compared to the kinematic restoration. This proves this approach can offer a significant advance in the study of the basin, by not only providing the stress and strain distribution and salt geometry at present day, but also reproducing their evolution during the Tarfaya basin history. Sensitivity analysis on the evolutionary model indicates that temporal and spatial variation in sedimentation rate is a key control on the kinematic structural evolution of the salt system. The variation of sedimentation rates in the model controls whether the modelled salt body gets buried by Tertiary sediments (after a continuous growth during the Jurassic and Cretaceous periods) or is able to remain active until the present day. Also, the imposed shortening affects the final stress distribution of the sediments at the present day. To conclude, the results obtained during this study allowed us to understand the formation and evolution of the diapirs in the Tarfaya basin using carefully built geomechanical models. The study demonstrates that carefully built 2D static models can provide information comparable to the 3D models, but without the time and computational power requirements of the 3D models. That makes the 2D approach very appropriate for the exploration stages of a particular prospect. If carefully built, such 2D models can approximate and yield useful information, even from complex 3D structures such as the Tarfaya basin salt structures. This thesis also concludes that incorporating kinematic restoration data into 2D evolutionary models provides insights into the key parameters controlling the evolution of the studied system. Furthermore, it enables more realistic geomechanical models, which, in turn, provide more insights into sediment stress and porosity.

Outcrop analogue studies of fluvial sedimentary systems are often undertaken to identify spatial and temporal characteristics (e.g. stacking patterns, lateral continuity, lithofacies proportions). However, the lateral extent typically exceeds that of the exposure, and/or the true width and thickness are not apparent. Accurate characterisation of fluvial sand bodies is integral for accurate identification and subsequent modelling of aquifer and hydrocarbon reservoir architecture. The studies presented in this thesis utilise techniques that integrate lidar, highresolution photography and differential geospatial measurements, to create accurate three-dimensional (3D) digital outcrop models (DOMs) of continuous 3D and laterally extensive 2D outcrop exposures. The sedimentary architecture of outcrops in the medial portion of a large Distributive Fluvial System (DFS) (Huesca fluvial fan) in the Ebro Basin, north-east Spain, and in the fluvio-deltaic succession of the Breathitt Group in the eastern Appalachian Basin, USA, are evaluated using traditional sedimentological and digital outcrop analytical techniques. The major sand bodies in the study areas are quantitatively analysed to accurately characterise spatial and temporal changes in sand body architecture, from two different outcrop exposure types and scales. Several stochastic reservoir simulations were created to approximate fluvial sand body lithological component and connectivity within the medial portion of the Huesca DFS. Results demonstrate a workflow and current methodology adaptation of digital outcrop techniques required for each study to approximate true geobody widths, thickness and characterise architectural patterns (internal and external) of major fluvial sand bodies interpreted as products of DFSs in the Huesca fluvial fan, and both palaeovalleys and progradational DFSs in the Pikeville and Hyden Formations in the Breathitt Group. The results suggest key geostatistical metrics, which are translatable across any fluvial system that can be used to analyse 3D digital outcrop data, and identify spatial attributes of sand bodies to identify their genetic origin and lithological component within fluvial reservoir systems, and the rock record. 3D quantitative analysis of major sand bodies have allowed more accurate width vs. thickness relationships within the La Serreta area, showing a vertical increase in width and channel-fill facies, and demonstrates a 22% increase of in-channel facies from previous interpretations. Additionally, identification of deposits that are products of a nodal avulsion event have been characterised and are interpreted to be the cause for the increase in width and channel-fill facies. Furthermore, analysis of the Pikeville and Hyden Fms contain sand bodies of stacked distributaries and palaeovalleys, as previously interpreted, and demonstrates that a 3D spatial approach to determine basin-wide architectural trends is integral to identifying the genetic origin, and preservation potential of sand bodies of both palaeovalleys and distributive fluvial systems. The resultant geostatistics assimilated in the thesis demonstrates the efficacy of integrated lidar studies of outcrop analogues, and provide empirical relationships which can be applied to subsurface analogues for reservoir model development and the distribution of both DFS and palaeovalley depositional systems in the rock record.

La géothermie est devenue aujourd’hui l’une des solutions pour produire de l’énergie tout en limitant significativement les émissions de gaz à effet de serre dans l’atmosphère. Cette énergie de base renouvelable qui exploite la chaleur souterraine présente de nombreuses utilisations comme la production de chaleur, de froid et/ou d’électricité. Cependant la facilité d’accès à cette ressource n’est pas la même partout et seuls quelques sites privilégiés sont recensés dans le monde. Le réservoir géothermique doit en effet être perméable et facilement accessible.Les îles des Petites Antilles s’inscrivent dans un contexte géologique de subduction favorable à l’existence de réservoirs géothermiques. Toutefois, l’insularité et le caractère volcanique complexifient l’exploration qui nécessite des échelles spatiales plus fines. À ces difficultés s’ajoutent la proximité de la mer qui perturbe notamment les méthodes électromagnétiques, la végétation dense favorisée par le climat tropical et la forte urbanisation.Face à ces nombreux obstacles, il est indispensable d'appliquer des méthodologies adaptées qui aboutissent à l'élaboration de modèles conceptuels les plus complets et surtout les plus fiables possibles. La modélisation numérique peut y apporter une grande fiabilité et réduire ainsi le risque géologique.Une méthodologie de couplage de modèles numériques est présentée et appliquée au prospect géothermique du Lamentin en Martinique, mais vise à être adaptée aux autres îles des Petites Antilles, voire à d’autres zones insulaires et volcaniques. Le logiciel Geomodeller et la plateforme ComPASS sont les deux outils numériques qui ont été employés pour générer un modèle géologique 3D et pour y réaliser des simulations hydro-thermiques. La construction du modèle 3D apportera des éléments de compréhension et de réflexions sur la structure et le fonctionnement du système géothermique du Lamentin. La comparaison des géothermes obtenus par simulation hydro-thermique avec ceux mesurés dans les forages d’exploration profonde permettront d’éprouver certaines hypothèses sur la localisation et l’intensité de la source de chaleur responsable de l’activité hydrothermale du Lamentin
Geothermal energy has become one of the recognized processes to supply energy and to stop significantly the emission of greenhouse effect gases in the atmosphere. This classical renewable energy consists to extract thermal energy into the Earth and to produce heat, cooling and/or electricity. But particularly for the last case, only a few places in the world can exploit it. Indeed, the geothermal reservoir must be permeable and easily accessible.The subduction setting of the Lesser Antilles is favorable to the presence of geothermal reservoirs but its insularity and its volcanic nature have a negative impact on the exploration phases. The influence of the sea on electromagnetic methods, dense bush and the strong urban development add other obstacles. Thus, the risk of failure increases. Consequently, the localization and the characterization of the geothermal reservoir must be more precise. Facing these many constraints, it is essential to apply adapted methodologies and to build the best conceptual model as possible.The coupling of numerical models is presented and applied to the low enthalpy geothermal system of Lamentin, in Martinique. This approach could be developed for other countries with the same geodynamical context. The Geomodeller software and the ComPASS Code are the two numerical tools which have been employed to generate a 3D geological model then to simulate the hydrothermal aspect.The building of the 3D model gives elements of knowledge and thinking about the geothermal system of Lamentin and the hydrothermal simulations suggest some hypothesis on the localization and the intensity of the heat source

En tant que géoscientifique dans le domaine de l’Exploration pétrolière et gazière depuis une vingtaine d’années, mes fonctions professionnelles m’ont permis d’effectuer différents travaux de recherche sur la thématique de la gestion des risques et des incertitudes. Ces travaux de recherche se situent sur l’ensemble de la chaîne d’analyse Exploration, traitant de problématiques liées à l’acquisition et au traitement sismique, jusqu’au placement optimal de forages d’exploration. Un volet plus poussé de mes travaux s’est orienté sur la gestion des incertitudes géophysiques en Exploration pétrolière, là où l’incertitude est la plus importante et paradoxalement la moins travaillée.On peut regrouper mes travaux de recherche en trois grands domaines qui suivent les grandes étapes du processus Exploration : le traitement sismique, leur interprétation, et enfin l'analyse et l'extraction des différentes incertitudes qui vont nous permettre de calculer les volumes d’hydrocarbures en place et récupérables, ainsi que l’analyse de ses risques associés. L’ensemble des travaux de recherche ont été appliqués avec succès sur des cas d’études opérationnelles. Après avoir introduit quelques notions générales et détaillé les grandes étapes du processus Exploration et leur lien direct avec ces problématiques, je présenterai quatre grands projets de recherche sur un cas d’étude algérien
In the last 20 years, I have been conducting various research projects focused on the management of risks and uncertainties in the petroleum exploration domain. The various research projects detailed in this thesis are dealing with problematics located throughout the whole Exploration and Production chain, from seismic acquisition and processing, until the optimal exploration to development wells placement. Focus is made on geophysical risks and uncertainties, where these problematics are the most pronounced and paradoxically the less worked in the industry. We can subdivide my research projects into tree main axes, which are following the hydrocarbon exploration process, namely: seismic processing, seismic interpretation thanks to the integration with various well informations, and eventually the analysis and extraction of key uncertainties, which will be the basis for the optimal calculation of in place and recoverable volumes, in addition to the associated risk analysis on a given target structure. The various research projects that are detailed in this thesis have been applied successfully on operational North Africa and North Sea projects. After introducing risks and uncertainty notions, we will detail the exploration process and the key links with these issues. I will then present four major research projects with their theoretical aspects and applied case study on an Algerian asset

The Vajont landslide is one of the largest catastrophic slope failures of the past century. About 270 million m3 of limestones, mudstones and marls slid into the Vajont Reservoir on October 9, 1963, producing a displacement wave that overtopped the dam and killed over 2000 people in the valley below. Although the landslide has been extensively studied over the past several decades, its morphologic and structural controls, mechanisms, and dynamics are not completely understood yet. The first step in carrying out the research was the implementation of a bibliographic and geographic electronic geo-databases, including all existing bibliographic records. Published documents, theses, unpublished technical reports and maps were collected and indexed and they are available for the scientific community. Afterwards, new techniques and technologies which were not available yet in the 60’s, were applied to this thesis in order to investigate more in detail the morpho-structural features and to better understand the different role that they played in the 1963 event, thus providing a more rigorous and less empirically based forecasting approach to the study of large catastrophic landslides. In particular, the applied remote sensing techniques (DEM analyses, LIDAR technologies, photogrammetric analyses) allowed to characterize in detail the structure of inaccessible areas of the failure surface and, along with the geological and geomechanical field investigations, to clarify relevant aspects concerning the geological-structural setting of the northern slope of Mount Toc. The geomechanical survey in 89 stations was performed in order to reach an accurate knowledge and in-depth evaluation of the characteristics of the rock masses outcropping on the Vajont area, both inside and outside the landslide. The obtained results permitted the identification of the most significant parameters that influenced the rockslide triggering and displacement, so helping in the comprehension of both the phenomenon and the structural control on its development and collapse. The implementation of laboratory tests Uniaxial and Triaxial on rock samples completed the geomechanical characterization of the rock-masses. The amount of the collected data were used to characterize the rock mass quality, through the following different classifications : Rock Quality Designation (RQD) Rock Mass Rating System (RMR) and Slope Mass Rating (SMR). In order to complete the knowledge of the deep geological structure of the rock masses two seismic reflection profiles were carried out. The results of their preliminary interpolation are still in progress. The accurate and detailed results achieved of the above mentioned techniques, combined with field investigations, laboratory tests and ongoing geophysical surveys allowed to obtain a reliable 3D geological model. This above mentioned 3D model firstly allowed to define the sliding surface depth and geometry more precisely than ever, and secondly to evaluate the landslide kinematics. These aspects represent the fundamental starting point for the future 3D modelling elaborations.
La frana del Vajont è uno dei piu’ grandi eventi catastrofici del secolo scorso. Il 9 ottobre 1963, Circa 270 milioni di m3 di calcari, marnosi precipitarono nel bacino del Vajont .producendo un onda che oltrepasso’ la diga uccidendo piu’ di 2000 persone nella valle sottostante. Nonostante nei decenni passati la frana sia stata approfonditamente studiata, il controllo morfologico e strutturale, i meccanismi e le dinamiche non sono state ancora completamente chiarite. Il primo step del progetto di ricerca è stata la costruzione di un GIS-database contenente tutte le informazioni, edite ed inedite, collezionate sulla frana del Vajont (articoli, report, tesi e rapporti scientifici, carte geologiche e topografiche). Successivamente nuove tecniche e tecnologie non disponibili negli anni 60, sono state utilizzate nel presente lavoro per analizzare in dettaglio le caratteristiche morfo-strutturali e per megli comprendere il differente ruolo che hanno rivestito nell’evento del 1963, fornendo di conseguenza metodi di previsione piu’ scientificamente piu’rigorosi per la previsione delle grandi eventi catastrofici. In particolare, le tecniche remote sensing utilizzate (analisi DEM, tecnologie Lidar e analisi fotogrammetriche) hanno consetito di caratterizzare in dettaglio le caratteristiche strutturali di aree poco accessibili sulla superficie di scivolamento e, congiuntamente alle indagini di campagna, di chiarire gli aspetti rilevanti circa l’assetto geologico del versante Nord del Monte Toc. .Al fine di ottenere un’accurata conoscenza e una approfondita valutazione delle caratteristiche degli ammassi rocciosi affioranti fuori e dentro l’area della frana, le indagini geomeccaniche sono state condotte su 89 stazioni di misura. I risultati ottenuti hanno permesso di identificare i parametri più significativi che hanno influenzato l’innesco e l’evoluzione della frana favorendo così la comprensione del fenomeno in termini di sviluppo e collasso. L’implemetazione dei test di laboratorio, (prove uniassiali e triassiali) sui campioni di roccia hanno completato la caratterizzazione geomeccanica degli ammassi rocciosi. La consistente quantità di dati ottenuti è stata utilizzata per caratterizzare gli ammassi rocciosi attraverso differenti classificazioni standard tra cui RQD (Rock Quality Designation), (RMR) Rock Mass Rating System e SMR (Slope Mass Rating). Al fine di investigare sulla struttura geologica del versante Nord del Monte Toc, sono stati realizzati due profili ssismici. Attualmente è in corso l’analisi preliminare dell’interpolazione. Inoltre la costruzione del primo modello geologico 3D della frana ha permesso di analizzare dettagliatamente la cinematica della frana e di definire la geometria e la profondità della superficie di scivolamento. Gli accurati e dettagliati risultati raggiunti mediante l’utilizzo di nuove tecniche e di tradizionali indagini di campagna completate dai test di laboratorio ha permesso di ottenere un attendibile modello geologico 3D e un quadro completo delle caratteristiche geomeccaniche, che costituiscono una base fondamentale per l’elaborazione futura di modelli 3D

Los medios fracturados de baja permeabilidad (MFBP) pueden definirse como una matriz impermeable atravesada por una cantidad mayor o menor de fracturas conductivas. La experiencia indica que la mayor parte del flujo circula solo por unas pocas de estas fracturas, característica que marca el comportamiento del medio. Por esto, es necesario caracterizar estas fracturas para comprender el sistema.
Desgraciadamente, no existe una metodología ampliamente aceptada para ello, en este contexto el objetivo de esta tesis es triple:
1. Definir una metodología para modelar este tipo de medios
2. Explicar cómo la modelación explícita de las principales fracturas ayuda a explicar el efecto escala.
3. Aplicar esta metodología a dos casos reales: FEBEX en Grimsel y Mina Ratones en Cáceres.
La tesis está formada por tres artículos independientes pero complementarios, que se describen a continuación.
En el primero se presenta la metodología para identificar las fracturas hidráulicamente más importantes. El método se basa en la interpretación de los ensayos de interferencia, y se apoya en los datos de geología, geofísica y ensayos hidráulicos. La metodología se ha aplicado en la caracterización hidrogeológica del bloque granítico que rodea al experimento FEBEX, en Suiza. La caracterización de este medio comienza por la identificación geométrica de las fracturas, basada en datos geológicos y geofísicos. Los ensayos hidráulicos de sondeo único ayudan a descartar aquellas fracturas no transmisivas, pero las conectividades entre puntos y la extensión de las fracturas se realiza mediante ensayos de interferencia. La geometría resultante se reproduce con un modelo 3D, donde los planos de fractura se representan con elementos 2D incluidos en la matriz 3D (matriz más fracturación menor). Los parámetros hidráulicos se obtienen de la interpretación conjunta de todos los ensayos de interferencia con modelos numéricos 3D, utilizando técnicas de calibración y ajustando todas las medidas simultáneamente. Siguiendo la misma metodología se ha podido reproducir los niveles en estacionario e incluso cuantificar el flujo de agua hacia la zona experimental de la galería FEBEX.
Una característica de los MFBP es que al aumentar el volumen de roca ensayado, la conductividad hidráulica equivalente obtenida aumenta. En el entorno de la galería FEBEX se han llevado a cabo diferentes tipos de ensayos hidráulicos (pulsos, recuperación, interferencia, etc.). Estos ensayos se han interpretado utilizando métodos convencionales, en los que se asume que el medio es homogéneo, y las conductividades hidráulicas obtenidas como resultado muestran un efecto de escala (aumentan en órdenes de magnitud con el volumen de roca ensayado). El objetivo de este trabajo es mostrar que este efecto de escala refleja las limitaciones de la conductividad hidráulica equivalente derivada de la interpretación de los ensayos con modelos homogéneos. Para alcanzar este objetivo se ha utilizado la metodología descrita en el artículo anterior. En resumen, el modelo final es coherente con todas las medidas tomadas a diferentes escalas. La mayor parte de los ensayos a pequeña escala se han realizado en intervalos situados en matriz, esto hace que la conductividad hidráulica equivalente promedio sea pequeña. Al aumentar la escala el ensayo afecta a más fracturas, con lo que aumenta la conectividad del sistema haciendo que la conductividad hidráulica equivalente aumente.
Finalmente, la metodología propuesta se aplica a la caracterización hidráulica de la mina de uranio "Los Ratones". Para verificar que la caracterización hidráulica ha sido satisfactoria, se ha realizado la predicción a ciegas de un bombeo a gran escala desde la mina. Los resultados obtenidos con esta simulación muestran unos buenos ajustes de los puntos de observación al bombeo desde la mina. Esto confirma la robustez y fiabilidad del modelo, y por lo tanto de la metodología utilizada.
Low permeability fractured media (LFFM) can be viewed as consisting of a virtually impervious matrix transversed by more or less conductive fractures.
Experience dictates that a few of these concentrate most of the flow, this controlling the overall behaviour of the medium. Therefore, they need to be characterized for proper understanding of the system. Unfortunately, no widely accepted methodology is available to this end. In this context the objective of this thesis is three fold:
1. Define a methodology to model this type of media.
2. Explain how the explicit modeling of hydraulically dominant fracture helps in explaining scale effects.
3. Apply the methodology to two real case studies: the FEBEX at Grimsel and the Ratones mine.
The thesis consists of three independent but complementary papers. They are described below.
First, I present a methodology to identify the most significant water conductive fractures. The method is based on the interpretation of cross-hole tests, and is supported by geology, geophysics and hydraulic data. This methodology has been applied to the hydrogeological characterization of a granitic block within FEBEX experiment, Switzerland. Characterising this medium starts by achieving a geometrical identification of the fractures, which demands mainly geological and geophysical data. Single borehole hydraulic tests help in neglecting those transmissive fractures, but the only means to assess the connectivity between points and the fractures extent consists of conducting cross-hole tests. The resulting geometry is later implemented into a 3D finite element mesh, where the fractures are simulated as 2D elements that are embedded into a 3D porous media that includes the effect of minor fractures. Hydraulic parameters have been obtained from the joint interpretation of cross-hole tests with 3D numerical models, using automatic calibration techniques and adjusting all the measurements simultaneously. This methodology has proved capable of reproducing steady state heads, and also of quantifying groundwater flow to the experimental area of the FEBEX tunnel.
Different types of hydraulic tests (pulse, recovery, cross-hole and tunnel inflow measurements) have been performed in low permeability fractured granite around the FEBEX tunnel in Grimsel (Switzerland). We have interpreted the tests using conventional methods that treat the medium as a homogeneous one. Results display scale effects. Hydraulic conductivities increase, by orders of magnitude, with the volume of rock tested (from pulse to cross-hole tests). The objective of our work is to show that this scale effect is apparent. It reflects the limitations of the equivalent hydraulic conductivity derived from the homogeneous model interpretation of the tests.
For this purpose, we have used the methodology described in the first paper. In summary, the final model is consistent with all the relevant measurements, taken at different support scales. This provides some insight into the issue of scale effects, which has been a topic of debate in the literature. In essence, the majority of small scale tests are performed in matrix intervals. Thus, any averaging of these values would suggest relatively small effective permeability. Yet large scale permeability of the rock is controlled by a few fractures, which provide high connectivity to the system, but are intersected by few testing intervals. As a result, large scale permeability is qualitatively different and quantitatively larger than small scale permeability.
Finally, the proposed methodology is applied to the hydraulic characterization of the "Los Ratones" uranium mine. To verify that the site characterization is satisfactory, a blind-prediction has been carried out with the data recorded during a large-scale pumping test from the mine. The results obtained with this simulation show a good response to the mine pumping, so that both the robustness and reliability of the model are confirmed.

Despite increasing computer power, the requirement to upscale 3D geological models for dynamic reservoir simulation purposes is likely to remain in many commercial environments. This study established that there is a relationship between sandbody size, cell size and changes to predictions of reservoir production as grids are upscaled. The concept of a cell width to sandbody width ratio (CSWR) was developed to allow the comparison of changes in reservoir performance as grids are upscaled. A case study of the Flounder Field in the Gippsland Basin resulted in the interpretation of three depositional environments in the intra-Latrobe reservoir interval. The sandbody dimensions associated with these depositional environments were used to build a series of 3D geological models. These were upscaled vertically and horizontally to numerous grid cell sizes. Results from over 1400 dynamic models indicate that if the CSWR is kept below 0.3 there will be a strong correlation between the average production from the upscaled grids compared to those of a much finer grid, and there will be less than 10% variation in average total field production. If the CSWR is between 0.3 and 1, there could be up to 30% difference, and once the CSWR exceeds 1.0 there is only a weak relationship between the results from upscaled grids and those of finer grids. As grids are upscaled the morphology of bodies in facies models changes, the distribution of petrophysical properties is attenuated and the structure is smoothed. All these factors result in a simplification of the fluid flow pathways through a model. Significant loss of morphology occurs when cells are upscaled to more than a half the width of the reservoir body being modelled. A simple rule of thumb is established — if the geological features of a model cannot be recognised when looking at a layer in the upscaled grid, the properties of the upscaled grid are unlikely to be similar to those of the original grid and the predictions of dynamic models may vary significantly from those of a finer grid. This understanding of the influence of sandbody size on the behaviour of upscaled dynamic models can be used in the planning stages of a reservoir modelling project. Two simple charts have been created. The first chart is for calculating the approximate number of cells in a model before it is built. The second chart is for comparing the proposed cell size against the CWSR, so that the predicted discrepancy between the ultimate production from the upscaled grid and one with much smaller cells can be assessed. These two charts enhance discussion between all interested disciplines regarding the potential dimensions of both static and upscaled dynamic models during the planning stage of a modelling project, and how that may influence the results of dynamic modelling.
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Thesis (Ph.D.) - University of Adelaide, Australian School of Petroleum, 2009

The primary aim of this dissertation is to map the geology of the East Rand Basin accurately by creating a 3D model. This was done by using borehole data from the National Groundwater Archive Geodatabase, which the Department of Water and Sanitation collected, and the average depths derived from the literature. Triangulated irregular networks (TINs) and digital elevation models (DEMs) surfaces were created from these data points to determine the depths for areas with no borehole data. Using these surfaces, three methods were used to create three main models. These models were then compared to one another, other geological maps and cross-sections to determine the most accurate and practical model of the three. It was found that the quality and quantity of the data from the National Groundwater Archive Geodatabase were not sufficient for these models; therefore, the results and accuracy of each layer was questionable. This dissertation found that these methods can be used for basic geological studies if the data are of the same quality and quantity. However, if the data are more evenly distributed and higher in quantity, these methods can be used to create more accurate models. Furthermore, the use of commercial software was recommended in this study. The reason for recommending these tools is that they have been specifically designed to create geological layers from boreholes within the ArcGIS software. These tools also allow the user to create cross-sections within ArcGIS.
MSc (Geography and Environmental Management), North-West University, Potchefstroom Campus, 2015

The dissertation be about use the opportunity of 3D modelling geological settings for definitions engineering geology zoning. The model area represents the map sheet 6 - 8 Kralupy nad Vltavou in scale 1:5 000, which is built by rocks (pre-Quaternary) and soils (Quaternary cover) divided into eleven engineering geology zones. The results of modelling are showing at the map appendices, which are engineering maps all of nine the individual roof (surface) of zones, including the 3D section in the direction of x axis and also five of the 2D maps of roof of selected zones with the 3D schematic models. The integral part is the map of documentation points and their database on DVD. Three dimensional modelling presents a benefit mainly therefore the solutions, where are visible the spatial geological settings including the thickness individual layers, respectively zones. These display options can have practically used at designing underground buildings, e.g. tunnels, where would it mean shortening time the preparation of the project. Modelling of the zones also shown a possibility of distinction the mistakes at some archive hole. For example, the mistakes in descriptions can relate to confusion of Neogene's sand layer for Quaternary's sand. In the description of new geological survey, when using appendix no....

Il presente lavoro di dottorato si è posto l’obiettivo di caratterizzare la sismicità indotta dalle attività di produzione di idrocarburi della Val d’Agri intesa come valle intramontana che comprende il bacino del fiume Agri e le dalle strutture appenniniche più esterne, al cui interno ricadono la concessione di coltivazione omonima e la diga del Lago Pertusillo. L’attività svolta ha riguardato la definizione di un nuovo modello geo-strutturale pseudo -3D, di maggiore dettaglio rispetto a quanto disponibile in letteratura, utilizzato per la caratterizzazione della sismicità nell’area di studio (es. Candela et al. 2015 e Buttinelli et al. 2016). Infatti, il modello realizzato è stato ricostruito attraverso un set di dati innovativo: dati di superficie rilevati, di sottosuolo messi a disposizione dalla società Eni S.p.A. e dataset riprocessato con metodi avanzati relativo alla sismicità registrata reso disponibile da INGV. L’analisi integrata di tutti questi dati ha permesso di realizzare un modello strutturale ben vincolato e geologicamente affidabile in grado di meglio rispondere ai diversi quesiti di carattere geodinamico, tettonico e sismologico che riguardano la conoscenza di questa complessa area di studio. Con particolare riguardo alla sismicità strumentale, i risultati del lavoro di dottorato mostrano una prima possibile caratterizzazione della sismicità registrata a ovest e a est del bacino della Val d’Agri attraverso il modello dei graviquakes (Doglioni et al., 2014 e 2015), identificando le strutture, le unità coinvolte, le loro proprietà fisiche, e i meccanismi determinanti nella generazione degli eventi sismici. I risultati relativi alla caratterizzazione della sismicità attraverso il modello dei graviquakes trovano supporto nelle evidenze di recenti studi disponibili in letteratura (Balasco et al. 2021; Vadacca et al. 2021).
The present Ph. D thesis aims to characterize seismicity induced by hydrocarbon production in Val d’Agri, an intramontain valley that includes the Agri river basin and the outermost Apennine structures, where the homonymous exploitation licence and the Pertusillo Lake dam are located. The activity carried out concerned the definition of a new pseudo - 3D geo-structural model alternative and more detailed with respect to those available in literature, used to characterize seismicity in the study area (e.g. Candela et al. 2015 and Buttinelli et al. 2016). In fact, the realized structural model is based on an innovative dataset costituted by: field data collected, underground data provided by Eni S.p.A. and a reprocessed dataset with advance techniques on recorded seismic events provided by INGV. Integrated analysis of these data allows to realize a very well constrained and reliable structural model that supplies several evidences answering many of the open questions on geodynamic, tectonic, and seismic field retracing important steps in the knowledge evolution of this complex study area. Regarding seismicity, the results of this thesis show a possible characterization of recorded events at west and east of the Val d’Agri basin through graviquakes model (Doglioni et al., 2014 e 2015) identifying structures, units involved, their physical properties and the most relevant mechanisms in generation of seismic events. The results on seismicity characterization adopting the graviquakes model is consistent with recent studies (Balasco et al. 2021; Vadacca et al. 2021).

The Lower Ordovician El Paso Group is a >400-m-thick carbonate succession exposed in the Franklin Mountains, El Paso, Texas. The El Paso Group contains multiple breccias related to collapsed-paleocave systems. These breccias have been documented as having formed during the top-Lower Ordovician Sauk depositional supersequence lowstand. Evidence presented in this study suggests that cave formation may have been as much as 350 million years younger and related to Laramide oblique right lateral compression. Regardless of the timing of formation, the breccias mapped in this study are of collapsed paleocave origin based on breccia clast organization and matrix content. Speleogenetic models are compared against observations of breccia distribution by direct field observations and mapping on sub-meter airborne light detection and ranging or lidar data. Point vectors were defined for every point within study area to highlight subtle changes in outcrop erosional profile for mapping geological features directly on the lidar point cloud. In addition, spectral data from airborne photography and hyperspectral image analysis were used assist in geological contact definition. A digital outcrop model was constructed from 3D geologic mapping results from which spatial statistic were extracted and used to reconstruct collapsed paleocave breccia bodies. The resultant breccia geometries were compared against laser-scanned modern cave dimensions, from Devil's Sinkhole, Rocksprings, Texas, and used in analysis of conceptual models for cave formation. The breccias of the southern Franklin Mountains follow linear trends that closely match Riedel shear fracture patterns predicted from right-lateral oblique compression. Stress orientations that match right-lateral oblique compression in the Phanerozoic of the El Paso region are related to the Laramide orogeny. The relationship of observed structures and the orientation of collapse breccias may indicate that southern Franklin Mountain breccia bodies are the result of a solution-enhanced tectonic karst system.
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