Faculty of Mining, Geology and Petroleum Engineering Repository
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Korištenje geoloških formacija za skladištenje različitih oblika energije : završni rad
No full textDa bi se ostvarila energetska tranzicija neophodno je povećati korištenje obnovljivih izvora energije te minimalizirati rasipanje energije, na način da se višak energije uskladišti. Upravo kod rješavanja ovoga problema neophodno je podzemno skladištenje energije. Postoji nekoliko tehnologija koje mogu biti održivo rješenje za podzemno skladištenje energije za razne vrste ležišta (podzemnih skladišta). Tehnologije koje će biti razmatrane u ovom radu su: podzemno skladištenje plina (engl. Underground Gas Storage, UGS), podzemno skladištenje vodika (engl. Underground Hydrogen Storage, UHS), skladištenje energije komprimiranim zrakom (engl. Compressed Air Energy Storage, CAES), podzemno hidro pumpno skladištenje (engl. Underground Pumped Hydro Storage, UPHS) i podzemno skladištenje toplinske energije (engl. Underground Thermal Energy Storage, UTES). Neke od ovih tehnologija mogu biti primjenjivane u svakom tipu ležišta, ali neke su strože po pitanju kriterija koji određuju prihvatljivost ležišta i mogu se primjenjivati samo u određenim tipovima ležišta, o čemu će također biti riječi u ovom radu
Classification of lithology in the northern Velebit using multispectral Sentinel-2 satellite imagery in the R programming language : master's thesis
No full textSvrha ovog rada je klasifikacija litologije određenog područja korištenjem multispektralnih satelitskih snimaka i programa R, izradio se algoritam koji se može primijeniti za bilo koje područje istraživanja i klasifikaciju litologije područja. Korištenjem softvera QGIS, izrađeni su poligoni starosti i vrste stijena kao ulazni podaci za napravljeni algoritam. Prostorna analiza se dobila pomoću R-a, preko integriranog razvojnog okruženja RStudio-a. Korištenjem nadzirane klasifikacije sustav se uvježbao, dobio je podatke te na temelju stečenog znanja detektirao nove podatke povlačenjem sličnosti između njih. Rezultat istraživanja je grafički prikaz tri modela rf, svm i nnet, gdje se odabire pouzdaniji model koji sadrži litologiju s ostalim klasama i spektralni potpisi multispektralnih satelitskih snimki Sentinel-2. Rad se može upotrijebiti kao podloga budućim istraživanjima u svrhu pronalaska naprednijeg sustava detekcije litologije područja istraživanja, koja sadržava informacije o starosti i vrsti stijena, čime inženjerima geologije omogućava brže i ekonomičnije istraživanje i razumijevanje geoloških karakteristika terena.The purpose of this study is the classification of lithology in a specific area using multispectral satellite imagery and the R programming language. An algorithm has been developed that can be applied to any research area for lithology classification. Using QGIS software, polygons of age and rock types were created as input data for the developed algorithm. Spatial analysis was performed using R through the integrated development environment of RStudio. Through supervised classification, the system was trained to acquire data and, based on the acquired knowledge, to detect new data by drawing similarities between them. The research results are graphically presented through three models: random forest (ri), support vector machine (svm), and neural network (nnet). The study aims to select the most reliable model that incorporates lithology with other classes and spectral signatures from Sentinel-2 multispectral satellite imagery. This work can serve as a foundation for future research aimed at developing an advanced system for detecting the lithology of research areas, including information about age and rock type. Such a system would enable geology engineers to conduct faster and more cost-effective research, enhancing their understanding of geological terrain characteristics
The influence of the inclination of passive ground anchors on the stability of the protective structure : master's thesis
No full textCilj ovog rada bila je analiza i usporedba utjecaja nagiba štapnih sidara na stabilnost zaštitne konstrukcije. Analiza rezultata napravljena je programskom paketu Plaxis, a proučavana su tri slučaja različitih nagiba sidra. U slučaju A pasivna sidra su duljine 6 m pod nagibom od 35°, u slučaju B pasivna sidra su duljine 6 m pod nagibom od 25° te u slučaju C pasivna su sidra duljine 6 m pod nagibom od 15°. Prikazane su teorijske osnove i vrste potpornih i zaštitnih konstrukcija, detaljnije su opisane zaštitne konstrukcije koje su bile tema ovog rada (sidra i mikropiloti), opisana je lokacija stambene zgrade koja služi kao podloga za analizu utjecaja nagiba sidra, prikazani su geotehnički istražni radovi i laboratorijska ispitivanja. Analizirani i uspoređivani su utjecaji nagiba sidra na dobivene vrijednosti horizontalnih pomaka pilota zaštitne konstrukcije, na vrijednosti momenata savijanja pilota zaštitne konstrukcije, na vrijednosti uzdužnih pomaka sidara te na vrijednosti uzdužne sile u sidrima. Analizom rezultata dobivenih za sva tri slučaja zaključeno je kako se najveća odstupanja javljaju u slučaju B, a u slučaju A i C rezultati su vrlo sličnih vrijednosti.The aim of this study was to analyze and compare the influence of the inclination of passive ground anchors on the stability of the protective structure. The results were analyzed using the Plaxis software package and three cases of different anchor inclinations were studied. In case A, the passive anchors are 6 m long at an inclination the 35°, in case B, the passive anchors are 6 m long at an inclination of 25°and in case C, the passive anchors are long 6 m at an inclination of 15°. The theoretical background and the types of supporting and protective structures are presented. The protective structures that were the subject of this study (anchors and micropiles) are desribed. The location of the residental building is described to serve as a basis for the analysis along with the presentation of influence of the anchor's inclination, geotehnical investigation works and laboratory tests. The primary analysis and comparison was between the influence of the anchor's inclination on the obtained values of the horizontal displacements of the piles of the protective structure, on the values of the bending moments of the piles of the protecite structure, on the values of the longitudinal displacement of the anchors and on the values of the longitudinal force in the anchors. When analyzing the results for all three cases it was found that the largest deviations occur in case B while in cases A and C the reuslts are of very similar
Extended-reach drilling (ERD)—the main problems and current achievements
No full textWith the development of different segments within the drilling technology in the last three decades, well drilling has become possible in harsh downhole conditions. The vertical well provides access to oil and gas reserves located at a certain depth directly below the wellsite, and a large number of vertical wells are required for the exploitation of hydrocarbons from spatially expanded deposits. However, the borehole can deviate from the vertical well, which means that the target zone can be reached by a horizontal directional well. With this type of well, especially in the case of drilling an extended-reach well (ERW), the length of the wellbore in contact with the reservoir and/or several separate reservoirs is significantly increased, therefore, it is a much better option for the later production phase. Unfortunately, the application of extended-reach drilling (ERD technology), with all of its advantages, can cause different drilling problems mostly related to the increased torque, drag, hole cleaning and equivalent circulation density (ECD), as well as to an increase in the well price. Overcoming these problems requires continuous operational change to enable operators to address downhole challenges. Today, the longest well reaches 15,240 m (50,000 ft), which raises the question of the technological and economic feasibility of this type of drilling project, especially with the lower oil price on the energy market. This paper provides a comprehensive overview of extended-reach drilling technology, discusses the main problems and analyzes current achievements
Estimation of precipitation fraction in the soil water of the hillslope vineyard using stable isotopes of water
No full textThis paper presents research related to the estimation of the precipitation fraction in the soil water of a sloped vineyard at the SUPREHILL Critical Zone Observatory (CZO) in Zagreb, Croatia. Numerous investigations have shown that exploration of hillslope soils can be very challenging due to the existence of heterogeneity and different soil properties, as well as due to anthropogenically induced processes, which can affect precipitation infiltration and soil water flow. Within this research, physicochemical soil properties, soil water content (SWC), and isotopic composition of soil water and precipitation (δ2H and δ18O) have been examined. The isotopic signature of soil water was monitored in 24 points, at 4 depths, throughout the hillslope vineyard. Soil water isotopic composition from all monitoring points coincided with the Local Meteoric Water Line (LMWL), with almost no variability at 100 cm depth, which was consistent with the smallest variation of SWC at 80 cm depth and indicated that most of water mixing takes place in the shallower part of the hillslope. Results suggested the existence of heterogeneity, uneven erosion processes in the footslope of the observed vineyard, and different infiltration patterns. Fractions of precipitation varied significantly depending on the depth and position in the vineyard, from approximately 1% up to 98%, where more precipitation fraction has been determined in the surface and subsurface runoff. Additionally, statistical analysis and a more detailed evaluation of precipitation fractions at the 40 cm depth, where wick lysimeters are installed, have shown that Corg content is related to the silt fraction, while the first results indicate that the infiltration patterns were dependent on the common influence of all observed physicochemical properties
Remediation of coal ash and slag disposal site : comparison of radiological risk assessments
No full textResiduals from coal combustion are known as a potential source of radiation exposure, especially in cases where the coal used in the combustion is characterized by increased radioactivity, resulting in coal ash and slag with potentially high activity concentration of radionuclides. This paper presents the results of the radiological risk assessments based on the ERICA Tool approach, used to estimate dose rates to terrestrial biota in the proximity of a coal fired thermal power plant in Croatia. The study consists of three radiological risk assessments using environmental data on activity concentration (Bqkg-1) from samples collected prior to the remediation of the disposal site and samples after the remediation implementation was completed. The resulting total dose rate to biota derived using data prior to the remediation ranged from 3.28 μGyh-1 to 147.68 μGyh-1. Assessment results of total dose rate based on the data from the studied area after remediation ranged from 0.23 μGyh-1 to 18.06 μGyh-1. The results showed that after the remediation only the total dose rate for lichens and bryophytes slightly exceeded ERICA Tool conservative screening value of 10 μGyh-1, which implies that environmental risks in relation to exposure to the disposal site can be considered negligible. The study results confirm the applicability of the ERICA Tool for the assessment of potential radiological impact and the effective remediation implementation at the coal and ash slag disposal site
Učinak piljenja dijamantnom žičnom pilom
No full textU radu su prikazani razvoj dijamantnih žičnih pila i konstrukcija dijamantne žice. Na temelju dosadašnjih istraživanja i iskustava, analizirani su učinci dijamantnih žičnih pila u kamenolomima vapnenca, travertina, mramora i granita. Poseban osvrt dan je na čimbenike koji utječu na učinkovitost piljenja. Neke od tih čimbenika nije moguće kontrolirati i vezani su uz karakteristike stijene koja se pili. Čimbenici koji utječu na učinkovitost, a moguće ih je djelomično kontrolirati, vezani su uz uvjete rada, karakteristike stroja i konstrukciju reznog elementa. U zaključku rada prezentirane su neke od smjernica za postizanje optimalnih učinaka pri piljenju dijamantnom žičnom pilom
Application of LAND-SUITE for landslide susceptibility modelling using different mapping units: a case study in Croatia
No full textLAND-SUITE software was applied to local-scale landslide susceptibility zonation in a study area (20 km) located in NW Croatia, which is characterised by small and shallow landslides in engineering soils and hard soils-soft rocks. Landslide susceptibility models were prepared using a LiDAR-based landslide inventory, and causal factors derived and/or modified using high-resolution remote sensing data. The landslide susceptibility analysis was carried out using different statistical methods and mapping units. As a result, we obtained ten susceptibility maps, classified into five zones based on modelled landslide probability. The main objective of this paper is to analyse the use of LAND-SUITE for deriving susceptibility zonations, useful to support applications in a spatial planning system on a local scale. One of the most valuable advantage of LAND-SUITE is that the selection of the appropriate causal factor maps can be performed using simple decisions based on multiple analyses, including multicollinearity tables and correlograms. The evaluation of the susceptibility models allowed to conclude that the pixel-based map represents the best option for application in a local-level spatial planning system, although it requires “post-processing” of the susceptibility zones to produce clustered and homogeneous information. LAND-SUITE has proven to be a valuable tool for testing numerous landslide susceptibility hypotheses
Pregled proizvodnje vodika postupkom pirolize metana i moguće primjene čvrstog ugljika : diplomski rad
No full textThe European Union aims to be climate-neutral by 2050, i.e., an economy with net-zero greenhouse gas emissions. This goal is compliant with European Green Deal and the European Union’s commitment to global climate action under the Paris Agreement. Hydrogen is seen as an important part of the solution to achieve this goal, but the positive impact of hydrogen on the mitigation of greenhouse gas emission relies heavily on the type of technology used to produce it. Methane pyrolysis is the thermal decomposition of natural gas into hydrogen and solid carbon. It produces CO2-free hydrogen, also known as turquoise hydrogen. Methane pyrolysis technologies fall into three categories: thermal, catalytic, and plasma decomposition. The technical challenges in the development of methane pyrolysis technology include the high energetic requirements and the separation of solid carbon in the reactor. This thesis provides a comprehensive overview of methane pyrolysis technologies currently under development. At the moment, plasma methane pyrolysis is the most advanced technology. Monolith Materials has been operating an industrial scale thermal plasma plant since 2020. The other technologies mentioned are still under development and are intended for pilot projects. For every tonne of hydrogen produced, three tonnes of solid carbon are also produced as a byproduct. Depending on the technology, methane pyrolysis can produce different types of solid carbon products, such as carbon black, carbon nanotubes, carbon nanofibers, graphite, graphene, etc. In this thesis, different types of carbon products that could be produced by methane pyrolysis are described in detail, especially their properties, most common present uses and possible future uses. The focus is on carbon black, as this is the largest and oldest market. However, if methane pyrolysis is carried out on an industrial scale, large amounts of solid carbon will be produced, and new markets for carbon products have to be found.Europska unija namjerava postići klimatsku neutralnost do 2050. godine, odnosno postati gospodarstvo s nultim neto emisijama stakleničkih plinova. Ovaj cilj je u skladu s Europskim zelenim planom i predanošću Europske Unije globalnoj klimatskoj akciji prema Pariškom sporazumu. Vodik se smatra značajnim dijelom rješenja za postizanje ovoga cilja, ali pozitivan učinak vodika na smanjenje stakleničkih plinova uvelike ovisi o vrsti tehnologije koja se koristi za njegovu proizvodnju. Piroliza metana je toplinsko cijepanje prirodnoga plina na vodik i čvrsti ugljik. Navedeni proces proizvodi vodik bez emisija ugljikovog dioksida koji je poznat i kao tirkizni vodik. Tehnologije pirolize metana se mogu podijeliti u tri kategorije: toplinska, katalitička i plazma piroliza. Izazovi za razvoj tehnologije pirolize metana uključuju visoke energetske zahtjeve i odvajanje čvrstog ugljika u reaktoru. Ovaj rad daje sveobuhvatan pregled tehnologija pirolize metana danas. Trenutno je plazma piroliza metana najnaprednija tehnologija (do danas je jedino kompanija Monolith Materials 2020. stavila u pogon termalno plazma postrojenje industrijskog razmjera). Ostale tehnologije su u razvoju s planovima za pilot projekte. Tijekom plazma pirolize na svaku proizvedenu tonu vodika, kao nusproizvod, proizvedu se i tri tone čvrstog ugljika. Ovisno o vrsti tehnologiji koja se koristi, pirolizom metana moguće je dobiti različite vrste čvrstog ugljika kao što su industrijska čađa, ugljikove nano-cijevi, ugljikova nano-vlakna, grafit, grafen, itd. Ovaj diplomski rad također detaljno opisuje različite vrste čvrstog ugljika koji bi se potencijalno mogli proizvesti pirolizom metana, točnije njihove značajke, najčešće uporabe danas i potencijalne buduće uporabe. Naglasak je stavljen na industrijsku čađu jer je to najveće i najstarije tržište. S obzirom da implementacija pirolize metana na industrijskoj razini ima za posljedicu proizvodnju velikih količina čvrstog ugljika, potrebno je pronaći nova tržišta za te proizvode