Correlation of rock quality designation and resistivity using unmanned aerial vehicle and two-dimensional electrical resistivity tomography

Rock Quality Designation (RQD) is a widely applied rock mass classification system for quantifying rock mass quality because it is simple and easily obtained compared to other rock mass classification systems. The rock mass quality using RQD can be identified from drill cores and scanline surveys. However, the calculation of RQD from core samples is expensive and directional-dependent. On the other hand, the scanline survey of obtaining RQD, provides point base information, is time-consuming, and is not practicable in large areas. In addition, the information by scanline survey is limited to the rock outcrop only, and subsurface rock mass quality remains unidentified. For subsurface investigation of rock mass conditions, 2D Electrical Resistivity Tomography (2D ERT) has been extensively applied; however, no comprehensive and detailed correlation of RQD and resistivity values exists to date. This study utilised an integrated Unmanned Aerial Vehicle survey (UAV) and 2D ERT survey at two sites with similar geological formations and aims to establish the correlation between resistivity and RQD indexes. The UAV survey enables the reconstruction of 3D point cloud that calculates the RQD on the surface indirectly from 1 m × 1 m block utilizing Volumetric Joint Count (Jv). This was achieved in ShapeMetrix (SMX) software. At the same time, the 2D ERT survey allows extracting the corresponding resistivity values for each RQD indexes from the same block using ZonRes2D software. A series of Linear Regression (LR) analysis and k-Nearest Neighbour (k-NN) algorithm were performed in Python to obtain continuous projections of RQD and rock resistivity and assigned resistivity values to respective RQD indexes. Two hundred twenty-three data points were obtained representing RQD and corresponding resistivity values. These data points successfully provide a continuous projection of RQD with resistivity using LR analyses, and it was confirmed that the resistivity of rock mass increases 30 Om for each unit increase in RQD index. Whereas the k-NN efficiently assigned resistivity values to various RQD indexes, the very poor rock shows a resistivity value of less than 350 Om; for poor rock, it ranges from 350-1150 Om. While for fair rock, the resistivity varies between 1150 to 1850 Om, for good rock, the resistivity ranges from 1850 to 2500 Om, and excellent rock has a resistivity value greater than 2400 Om. The established correlation of RQD obtained via k-NN characterize the surface and subsurface rock mass quality along the slope in RQD mapping. It was found that the subsurface rock mass quality was at higher quality compared to the surface at both sites. It can be concluded that the integrated UAV and 2D ERT have been successfully applied in this study. In addition, the established correlation will help in obtaining the RQD values using expeditious, inexpensive, and environmental non-destructive approach

Caracterização e estudo comparativo de exsudações de hidrocarbonetos e plays petrolíferos em bacias terrestres das regiões central do Irã e sudeste do Brasil usando sensoriamento remoto espectral

Orientador: Carlos Roberto de Souza FilhoTese (doutorado) - Universidade Estadual de Campinas, Instituto de GeociênciasResumo: O objetivo desta pesquisa foi explorar as assinaturas de exsudações de hidrocarbonetos na superfície usando a tecnologia de detecção remota espectral. Isso foi alcançado primeiro, realizando uma revisão abrangente das capacidades e potenciais técnicas de detecção direta e indireta. Em seguida, a técnica foi aplicada para investigar dois locais de teste localizados no Irã e no Brasil, conhecidos por hospedar sistemas ativos de micro-exsudações e afloramentos betuminosos, respectivamente. A primeira área de estudo está localizada perto da cidade de Qom (Irã), e está inserida no campo petrolífero Alborz, enterrado sob sedimentos datados do Oligoceno da Formação Upper Red. O segundo local está localizado perto da cidade de Anhembi (SP), na margem oriental da bacia do Paraná, no Brasil, e inclui acumulações de betume em arenitos triássicos da Formação Pirambóia. O trabalho na área de Qom integrou evidências de (i) estudos petrográficos e geoquímicos em laboratório, (ii) investigações de afloramentos em campo, e (iii) mapeamento de anomalia em larga escala através de conjuntos de dados multi-espectrais ASTER e Sentinel-2. O resultado deste estudo se trata de novos indicadores mineralógicos e geoquímicos para a exploração de micro-exsudações e um modelo de micro-exsudações atualizado. Durante este trabalho, conseguimos desenvolver novas metodologias para análise de dados espectroscópicos. Através da utilização de dados simulados, indicamos que o instrumento de satélite WorldView-3 tem potencial para detecção direta de hidrocarbonetos. Na sequência do estudo, dados reais sobre afloramentos de arenitos e óleo na área de Anhembi foram investigados. A área foi fotografada novamente no chão e usando o sistema de imagem hiperespectral AisaFENIX. Seguiu-se estudos e amostragem no campo,incluindo espectroscopia de alcance fechado das amostras no laboratório usando instrumentos de imagem (ou seja, sisuCHEMA) e não-imagem (ou seja, FieldSpec-4). O estudo demonstrou que uma abordagem espectroscópica multi-escala poderia fornecer uma imagem completa das variações no conteúdo e composição do betume e minerais de alteração que acompanham. A assinatura de hidrocarbonetos, especialmente a centrada em 2300 nm, mostrou-se consistente e comparável entre as escalas e capaz de estimar o teor de betume de areias de petróleo em todas as escalas de imagemAbstract: The objective of this research was to explore for the signatures of seeping hydrocarbons on the surface using spectral remote sensing technology. It was achieved firstly by conducting a comprehensive review of the capacities and potentials of the technique for direct and indirect seepage detection. Next, the technique was applied to investigate two distinctive test sites located in Iran and Brazil known to retain active microseepage systems and bituminous outcrops, respectively. The first study area is located near the city of Qom in Iran, and consists of Alborz oilfield buried under Oligocene sediments of the Upper-Red Formation. The second site is located near the town of Anhembi on the eastern edge of the Paraná Basin in Brazil and includes bitumen accumulations in the Triassic sandstones of the Pirambóia Formation. Our work in Qom area integrated evidence from (i) petrographic, spectroscopic, and geochemical studies in the laboratory, (ii) outcrop investigations in the field, and (iii) broad-scale anomaly mapping via orbital remote sensing data. The outcomes of this study was novel mineralogical and geochemical indicators for microseepage characterization and a classification scheme for the microseepage-induced alterations. Our study indicated that active microseepage systems occur in large parts of the lithofacies in Qom area, implying that the extent of the petroleum reservoir is much larger than previously thought. During this work, we also developed new methodologies for spectroscopic data analysis and processing. On the other side, by using simulated data, we indicated that WorldView-3 satellite instrument has the potential for direct hydrocarbon detection. Following this demonstration, real datasets were acquired over oil-sand outcrops of the Anhembi area. The area was further imaged on the ground and from the air by using an AisaFENIX hyperspectral imaging system. This was followed by outcrop studies and sampling in the field and close-range spectroscopy in the laboratory using both imaging (i.e. sisuCHEMA) and nonimaging instruments. The study demonstrated that a multi-scale spectroscopic approach could provide a complete picture of the variations in the content and composition of bitumen and associated alteration mineralogy. The oil signature, especially the one centered at 2300 nm, was shown to be consistent and comparable among scales, and capable of estimating the bitumen content of oil-sands at all imaging scalesDoutoradoGeologia e Recursos NaturaisDoutor em Geociências2015/06663-7FAPES

Hyperspectral Imaging for Fine to Medium Scale Applications in Environmental Sciences

The aim of the Special Issue “Hyperspectral Imaging for Fine to Medium Scale Applications in Environmental Sciences” was to present a selection of innovative studies using hyperspectral imaging (HSI) in different thematic fields. This intention reflects the technical developments in the last three decades, which have brought the capacity of HSI to provide spectrally, spatially and temporally detailed data, favoured by e.g., hyperspectral snapshot technologies, miniaturized hyperspectral sensors and hyperspectral microscopy imaging. The present book comprises a suite of papers in various fields of environmental sciences—geology/mineral exploration, digital soil mapping, mapping and characterization of vegetation, and sensing of water bodies (including under-ice and underwater applications). In addition, there are two rather methodically/technically-oriented contributions dealing with the optimized processing of UAV data and on the design and test of a multi-channel optical receiver for ground-based applications. All in all, this compilation documents that HSI is a multi-faceted research topic and will remain so in the future

Integrated Exploration, Geothermal Modelling and Techno-Economic Resource Assessment of the Crystalline Basement in the Northern Upper Rhine Graben

The climate crisis is already causing significant humanitarian and economic impacts that will intensify in the future if global greenhouse gas emissions are not immediately reduced. Under the Climate Protection Act, Germany is therefore obliged to achieve net carbon neutrality by 2045. To meet this ambitious target, a far-reaching transformation of the energy sector is necessary, with imports of fossil fuels being replaced by domestic renewable energy production. In addition to established energy sources, deep geothermal energy, as a low-emission, base-load capable, local and scalable solution, will likely become a cornerstone of energy supply in the upcoming decades. The crystalline basement offers the greatest geothermal potential, which could be exploited through so-called enhanced geothermal systems (EGS). Particularly favourable conditions for geothermal utilization exist in the Upper Rhine Graben (URG), where compared to other regions in Germany higher reservoir temperatures and permeabilities are observed. To date, however, deep geothermal energy occupies only a small niche due to the comparatively high costs and risks associated with drilling, development, and operation of geothermal power plants. In addition, geological uncertainties in the basement are particularly large, as it has been insufficiently explored by the hydrocarbon industry and previous geothermal research projects. This thesis aims to quantify and reduce these uncertainties to promote geothermal development in the northern URG. A comprehensive lithological, petrophysical and structural reservoir characterization is carried out by combining geological and geophysical techniques on multiple scales. All relevant data are integrated into a 3D geothermal model that enables a regional resource assessment for the basement. In the northern ORG, geologic modelling of the basement faces significant challenges because well data from the basement are very sparse and 3D seismic data are often not openly available. Therefore, gravity and magnetic data were additionally considered in a stochastic joint inversion that provided new insights into the structure and composition of the basement while also quantifying model uncertainties. The inversion demonstrates that the geologic units of the graben shoulders can be traced below the sedimentary filling. Comparison of the inverted petrophysical properties with existing databases and newly collected susceptibility measurements yielded a map of the predicted basement lithology in the northern URG. Accordingly, most areas are dominated by granitoids, which tend to have higher permeability than shales and gneisses and thus are preferred targets of geothermal drilling. In contrast, a predominantly metamorphic basement can be assumed in the Saxothuringian Zone and at the northwestern rift margin. The developed 3D basement model and inversion results were key input for a techno-economic resource assessment, which furthermore incorporated data from thermal and geomechanical models, operating geothermal power plants, and financial aspects of geothermal utilization. Calculation of resources at the regional scale was based on the widely used volumetric 'heat in place' method, whereby model uncertainties were quantified by means of Monte Carlo simulation. The recoverable heat along large-scale fault zones, considered as preferential fluid pathways, was estimated as a function of the slip and dilation tendency in the recent stress field. The economically exploitable part of the resources (reserves) was subsequently investigated by a sensitivity analysis of relevant parameters. The assessment reveals that the basement in the URG is characterized by a vast resource base, of which between 8 and 16 PWh are potentially recoverable with current EGS technologies. This could sustainably provide a significant fraction of the heat and power supply in the northern URG. About 65% of the resources were economically recoverable at market conditions in January 2022. In view of the enormous increases in energy prices resulting from the war in Ukraine, the share is now likely higher. A comparison of the calculated resources with the socio-economic-environmental conditions for geothermal utilization at the surface shows a high level of correlation, especially in the densely populated areas around Mannheim and Darmstadt. As groundwater flow in the crystalline basement is mainly controlled by open fractures, accurate knowledge of the natural fracture network is essential for the planning, development and operation of geothermal power plants. Image logs from deep boreholes provide the most meaningful information on fracture properties, but these are very rare and often inaccessible in the URG. A comprehensive structural outcrop analog study was conducted to compensate for the lack of borehole data. The Tromm Granite in the southern Odenwald was selected as the study area as it is both a suitable analog for the granitoid reservoirs in the northern URG and a potential site for the upcoming GeoLaB project. Here, lineament analyses and lidar surveys in abandoned quarries were combined, resulting in a multiscale description of the basement's fracture network. Discrete fracture network (DFN) models were then developed based on the obtained properties to estimate the permeability under assumed reservoir conditions. While the Tromm Granite is overall intensely fractured and the network is well connected, the density and orientation of fractures is strongly influenced by nearby fault zones. Fractures cluster roughly in the N-S direction, parallel to σHmax, resulting in an order of magnitude higher permeability than in the E-W direction. The structural investigations were complemented by geophysical surveys, designed to map and characterize the buried faults in the Tromm Granite. As in the regional modelling, potential field methods (terrestrial gravimetry and aeromagnetics) were applied and additionally the radon activity concentration was measured along one profile. The gravity data show rather broad anomalies, which cannot be assigned to single faults, but rather to zones of increased fault and fracture density. Inversion of the gravity data indicated a fracture related porosity of up to 9% along the pluton margins. The drone-based aeromagnetic survey, conversely, allows a more detailed mapping of the fault network. After filtering, the dataset revealed a complex network of linear anomalies that are interpreted as altered fault zones with increased reactivation potential, thus representing preferred fluid pathways. In conclusion, the crystalline basement is an attractive target for deep geothermal exploitation in the northern URG due to the vast resource base. As part of the dissertation, a new detailed geothermal 3D model and a regional map of the resources have been developed, providing politicians, investors, and project engineers with a more reliable basis for decision-making. Furthermore, the understanding of the fracture network properties and thus of the hydraulic properties in the northern URG was improved. Nevertheless, significant uncertainties remain at the local scale that can only be eliminated through targeted exploration measures and coupled numerical modelling. Besides, the risk of noticeable induced seismicity persists, which is a major obstacle to the exploitation of deep geothermal energy. Great hope therefore lies in the development of new safe stimulation techniques for EGS reservoirs, which will be advanced in particular within the framework of the upcoming GeoLaB project

Relations érosion : sédimentation entre le bassin du Qaidam (Tibet) et les chaines associées

The Qaidam basin, located within the northern Tibetan plateau, is the deepest intracontinental basin, yet located in the highest plateau with the thickest continental crust. Understanding how this peculiar basin developed has broad implications for the Tibetan geology in particular and for continental tectonics in general. Many approaches have been used to decipher the tectonic and topographic history of that region, however, the initial topography of the area now represented by the northern Tibetan plateau, as well as the early stages of development of the present day topography remain poorly constrained and highly debated. In order to better understand the Cenozoic evolution of the Qaidam basin and its surrounding regions (including Eastern Kunlun Range to the south, Altyn Tagh Range to the northwest, and Qilian Shan to the northeast), four critical issues are addressed in this thesis: 1) the Cenozoic joint tectonic evolution of the Qaidam basin and the Eastern Kunlun Range; 2) the interplay between the sedimentation within the Qaidam basin and the active tectonics within the Altyn Tagh Range; 3) a quantitative estimate of the lateral extrusion along the Altyn Tagh Fault-Qilian Shan tectonic system; 4) the nature and classification of the Qaidam basin. I suggest that the SW Qaidam basin has been bordered by a series of strike-slip faults to the south since the Early Miocene, rather than, as previously suggested by a continuous northward or southward thrusting system. Based on U-Pb dating (LA-ICP-MS) of detrital zircons collected from 4 sections (Paleocene to Holocene) within the southwestern Qaidam basin combined with provenance analysis and new seismic profile interpretation, I demonstrated that the Eastern Kunlun Range was already exhumed prior to the Paleocene. I show that the Qaidam basin was widening southward during thet early Cenozoic period (Paleocene to Oligocene). From Oligocene the relief of the Eastern Kunlun and Altyn Tagh ranges increased, leading to isolation and narrowing of the Qaidam basin from Miocene to the present. Along the northern edge of the basin, I identified the Tula-Huatugou and Anxi-Eboliang regions as residual parts of the original Qaidam basin. I suggest that the Altyn Tagh Fault has experienced a total of ~360 km of displacement since its Early Eocene initiation. Based on this ~360 km northeastward migration of the relatively rigid Qaidam block along the Altyn Tagh Fault and 3D isovolumetric balance of the crustal deformation within the Altyn Tagh Fault – Qilian Shan system, I demonstrate that 250 ± 28 km (43.8~49.4 %) of N20E directed crustal shortening and an additional ~250 to ~370 km of eastward motion of the Qilian Shan crust must be accounted for by strike-slip faulting in the Qilian Shan and crustal thickening in the Qinling area, as well as extension in the adjoining North China block graben systems.Le basin du Qaidam, situé sur la bordure nord du Plateau Tibétain est unique au monde en ce qu’il représente le bassin intracontinental le plus profond bien que situé sur le plus haut plateau et la plus épaisse croute continentale actuels. Comprendre le développement et l’évolution de ce bassin en lien avec la collision Inde-Asie a des implications multiples pour la géologie du Tibet en particulier et la tectonique continentale en général. De nombreuses études incluant de la thermochronologie, de la paléobotanique, du paléomagnétisme, de la paléoaltimétrie, de la sédimentologie et de la géologie structurale se sont intéressées à l’histoire tectonique et topographique de cette région. Toutefois la topographie initiale de la région actuellement représentée par le Plateau Tibétain ainsi que les premiers stades de développement du plateau restent méconnus et très débattus. Les travaux présentés ici sont basés sur des données de terrain, de sismique 2D et 3D, de géochimie, de géochronologie détritique, de sédimentologie et d’analyse d’images satellitaires. Ils décrivent: 1) l’évolution cénozoïque conjointe du bassin du Qaidam et de la chaine des Eastern Kunlun ; 2) les relations entre la sédimentation dans le bassin du Qaidam et la tectonique le long de la faille de l’Altyn Tagh ; 3) une estimation quantitative de l’extrusion latérale du nord Tibet les long du système Altyn Tagh – Qilian Shan ; 4) la nature et la typologie du bassin du Qaidam. Je démontre que la chaîne du Kunlun formait un relief en érosion au Paléocène et que la zone de dépôt du bassin du Qaidam s’est élargie vers le sud jusqu’à l’Oligocène. Dès le Miocène inférieur le SO du bassin du Qaidam était limité par un système tectonique décrochant. L’accroissement du relief dans les chaines du Kunlun et de l’Altyn Tagh entraine alors un isolement puis un rétrécissement du bassin. Je suggère que la faille de l’Altyn Tagh qui forme la bordure nord du Plateau, a accommodé environs 360 km de déplacement depuis sont initiation au Miocène inférieur. Cette déformation est prise en compte par du décrochement et de l’épaississement dans les Qilian Shan, de l’épaississement crustal dans les Qinling et de l’extension dans le système de grabens de Chine du Nord. Enfin, je conclu que le bassin du Qaidam est contrôlé conjointement par les failles décrochantes de l’Altyn Tagh et du Kunlun Est. La superposition dans le temps et l’espace des effets de ces deux décrochements majeurs durant le Cénozoïque a contrôlé l’évolution du bassin et la répartition des réserves d’huile et de gaz

Climate Change, Carbon Capture, Storage and CO2 Mineralisation Technologies

This Special Issue delivered 16 scientific papers, with the aim of exploring the application of carbon capture and storage technologies for mitigating the effects of climate change. Special emphasis has been placed on mineral carbonation techniques that combine innovative applications to emerging problems and needs. The aim of this Special Issue is to contribute to improved knowledge of the ongoing research regarding climate change and CCS technological applications, focusing on carbon capture and storage practices. Climate change is a global issue that is interrelated with the energy and petroleum industry