Faculty of Mining, Geology and Petroleum Engineering Repository
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Techno-economical analysis of CO2 pipeline transportation in the Republic of Croatia : master's thesis
No full textKaptiranje, korištenje i skladištenje ugljika predstavlja ključnu tehnologiju smanjenja emisija CO2 iz antropogenih izvora u elektroenergetskom i industrijskom sektoru. Potencijal za razvoj takve tehnologije u Republici Hrvatskoj je prepoznat na području Savske i Dravske depresije na osnovu moguće primjene CO2 za tercijarnu metodu proizvodnje na iscrpljenim naftnim poljima. Važan dio takvog projekta je planiranje i dimenzioniranje infrastrukture za transport CO2 koja će povezivati industrijske emitere sa iscrpljenim naftnim poljima. Najčešće se za kopneni transport koriste cjevovodi. Ugljikov dioksid je najučinkovitije transportirati u superkritičnoj fazi pri čemu se zahtijevaju specifični i visoki radni uvjeti u cjevovodu. U konačnici, radi se o kapitalno intenzivnom projektu čija se ekonomska prihvatljivost može procijeniti različitim metodama ocjene investicijskog ulaganja i analizom osjetljivosti.Carbon capture, utilization and storage is a key technology used to reduce CO2 emissions from stationary sources in the power and industrial sectors. The potential for the development of such technology in the Republic of Croatia has been identified in the Sava and Drava Depressions, based on the possible usage of CO2 for tertiary production method from depleted oil fields. An important part of such project is the planning and design of CO2 transportation infrastructure which connects industrial emitters and depleted oil fields. Pipelines are most frequently used in land transport. Carbon dioxide is most efficiently transported in a supercritical phase, which requires specific and high operating conditions of the pipeline. Lastly, it is a capital-intensive project whose economic viability can be estimated by various investment methods and sensitivity analysis
Causes of downhole equipment failures in production wells equipped with a sucker rod pumping system : master's thesis
No full textPrimjena dubinskih klipnih sisaljki s klipnim šipkama najstariji je i najčešće korišten sustav za prinudno podizanje kapljevine. Način rada sustava podrazumijeva prijenos energije i pogona od pogonskog motora na površini do niza klipnih šipki i dalje do dubinske klipne sisaljke. Podizanje fluida postiže se cikličnim kretanjem klipa prema gore i prema dolje. Tijekom rada u bušotini, dubinska oprema izložena je različitim tipovima opterećenja, i vibracijama, uz druge bitne elemente kao što su utjecaj tlaka i temperature te korozivnosti ležišnog fluida. Posljedično, nastaju značajna oštećenja i kvarovi povezani uglavnom s nizovima klipnih šipki i uzlaznih cijevi. Najčešće prisutni kvarovi su mehaničko trošenje spojnica klipnih šipki i propuštanje uzlaznih cijevi. Ostali primjetni kvarovi odnose se na dubinsku klipnu sisaljku i uključuju čepljenje sisaljke, propuštanje mirujućeg i putujućeg ventila te ispadanje klipa iz cilindra. Ovaj će rad donijeti pregled mogućih kvarova dubinske opreme u eksploatacijskim bušotinama koje su opremljene dubinskim sisaljkama s klipnim šipkama. Definirat će uzroke spomenutih kvarova uz rješenja i metode korištene s ciljem smanjenja njihove učestalosti. Nakon teorijskog objašnjenja, prikazat će oštećenja dubinske opreme na primjeru jednog hrvatskog naftnog polja.Sucker rod pumping is the oldest and most utilized artificial lifting system. The working principle of a system implies energy and power transportation from a surface power source to the sucker rod string and then to the sucker rod pump. Fluid lifting is achieved by a cyclic upward and downward movement of a plunger. During its stay in a well, downhole equipment is exposed to different types of load and vibrations along with other important elements like pressure and temperature influence or corrosiveness of a reservoir fluid. As a consequence, significant damages and failures occur, connected mostly with rod and tubing strings. The most frequent failures are rod string couplings mechanical wear and tubing leakage. The other notable failures refer to the sucker rod pump and include pump plugging, standing and travelling valve leakage and plunger dropping out of the cylinder. This thesis will present a review of potential downhole equipment failures in production wells equipped with a sucker rod pumping system. It will also define causes of the mentioned failures along with solutions and methods being utilized to reduce the frequency of their occurence . After theoretical explanation, an example of one Croatian oil field with downhole equipment failures will be given
Estimation of oscillation velocity during blasting in a quarry : master's thesis
No full textMiniranje je tehnika eksploatacije čvrstih mineralnih sirovina, iskopa u građevinarstvu te primjene eksploziva za različite ostale tehničke namjene. Raspoloživa energija eksploziva vrlo brzim kemijskim procesom transformira se u energiju stlačenih produkata eksplozije koji u ekspanziji obavljaju mehanički rad nad okolinom, odnosno drobe stijenu u oblik pogodan za preradu i upotrebu. Prilikom djelovanja eksploziva u minskom polju, na okolinu se javlja i neželjeni potresni odnosno seizmički utjecaj. Analiza utjecaja miniranja na lokaciji kamenoloma vapnenca i dolomita Špica je provedena u skladu s primijenjenim rješenjima miniranja. Pri tome su izdvojeni značajni utjecajni parametri te su definirani postupci za smanjenje brzina oscilacija, odnosno vibracija, kao mjere intenziteta i potencijalne štetnosti seizmičkog utjecaja miniranja.Blasting is a technique of exploitation of solid mineral raw materials, excavation in construction and application of explosives for various other technical purposes. The available energy of the explosive is transformed by a very fast chemical process into the energy of the compressed explosion products, which in the expansion perform mechanical work on the environment, that is, crush the rock into a form suitable for processing and use. During the action of explosives in a minefield, an unwanted shaking or seismic impact occurs on the environment. The analysis of the impact of blasting at the location of the Špica limestone and dolomite quarry was carried out in accordance with the applied blasting solutions. At the same time, significant influential parameters were identified and procedures were defined for reducing the speed of oscillations, that is, vibrations, as a measure of the intensity and potential damage of the seismic impact of blasting
Near wellbore damage of reservoir rocks and the removal of the damage trough the procedure of acidizing, on the example of sandstone and carbonate reservoirs : master's thesis
No full textKiselinske obrade ležišnih stijena jedna su od metoda stimulacije ležišta. Najjeftinija i najčešće korištena među njima je kiselinska obrada skeleta ležišne stijene, koja se temelji na utiskivanju kiseline u ležište, pri tlaku manjem od tlaka frakturiranja stijena. Kroz ovaj diplomski rad opisani su mehanizmi oštećenja ležišnih stijena te načini na koji se ta oštećenja manifestiraju, poput skin faktora. Također se u radu opisuju osnovni principi uklanjanja oštećenja ležišnih stijena hidrauličkim frakturiranjem kiselinom i kiselinskom obradom skeleta ležišne stijene. Dalje se opisuju kiseline korištene u takvim obradama te aditivi koji se dodaju u kiseline s ciljem prilagođavanja svake obrade specifičnim uvjetima u kojima se izvodi. U radu se stavlja naglasak na kiselinske obrade skeleta ležišne stijene zbog njihove ekonomičnosti i široke primjene. Detaljno su opisani postupci dizajniranja kiselinskih obrada skeleta ležišnih stijena karbonata i pješčenjaka. Ti postupci nisu samo opisani, već su i prikazani na primjerima kiselinske obrade skeleta izvedenih u Republici Hrvatskoj.Acidizing oil wells is a way of stimulating hydrocarbon reservoirs. The cheapest and most frequently used method of acidizing is matrix acidizing, which relies on pumping acid into the reservoir, at pressure rates which won't cause reservoir fracturing. This thesis defines wellbore damage, the mechanisms which cause it and how the damage is manifested, such as skin factor. Furthermore it describes the principles of damage removal trough the procedures of fracture acidization and matrix acidizing. It also describes the acids used in the procedures, as well as the additives used to design the acid for the specific conditions of every procedure. The thesis focuses on matrix acidizing, because of its cost-effectiveness and wide spread usage. It describes in detail the procedures of matrix acidizing of both sandstones and carbonates. These procedures are not only described, but also show using two real time examples
Epoxy coating modification with metal nanoparticles to improve the anticorrosion, migration, and antibacterial properties
No full textNanoparticles are capable of making more durable and stronger materials with better chemical resistance. They are used for a wide range of applications. Likewise, the potential of metal nanoparticles as antimicrobial agents has been widely studied. In this work, we investigate various nanoparticles (Al, Ni, Ag) incorporated into epoxy coating. The anticorrosion and antibacterial properties of the unmodified and modified coatings were evaluated. According to the SEM and EDS analyses, the coating did not contain agglomerates, which confirms the quality of the dispersion of inorganic nanoparticles in the coating. After 24 h and 10days immersions in a 3.5 wt.% NaCl solution, the corrosion behaviour for all nanocomposite was studied by means of EIS investigations. The study included the evaluation of the inhibition zone of the nanoparticles and the antimicrobial properties of the nanocomposite. It was found that the nanoparticles of Al and Ag provide excellent antibacterial properties. The epoxy nanocomposite with Al NP showed the migration of ions in the range from 0.75 to 1 mg/L in a wastewater solution for 30 days, indicating a potential for antimicrobe activity. The 1% Al NP epoxy nanocomposite showed good anticorrosion and antibacterial properties and demonstrated great potential for applications in pipelines
Feasibility study of managed aquifer recharge deployment on the island of Vis (Croatia)
No full textOver the last decades, the quality and quantity of the Mediterranean freshwater resources have significantly deteriorated due to climate change, unsustainable utilization, user conflicts, and seawater intrusions. On the small and remote island of Vis, where similar issues prevail, the need for alternative water management solutions has yielded managed aquifer recharge (MAR) as a promising option for increasing the safety and resilience of the local and autonomous water supply. By performing a cost–benefit analysis (CBA) to evaluate the feasibility of the deployment of an infiltration pond method in the Korita well field, the results evidenced a positive financial performance and sustainability of the proposed MAR solution. In addition, the overall economic benefits of the project, quantified through the willingness-to-pay method, significantly exceeded its costs, as evidenced by the high benefit/cost ratio of 2.83. The most significant uncertainty related to the infiltration pond method is represented by the high sensitivity to changes in the applied hydrological assumptions (i.e., the evaporation coefficient and number of annual infiltration pond recharges). This study aims to contribute to the understanding of interrelated socio-economic factors of MAR projects in karst aquifers, and represents the first of its kind in Croatia
Using dye and bromide tracers to identify preferential water flow in agricultural hillslope soil under controlled conditions
No full textProcesses in hillslope soils present a particular challenge for agricultural production and soil management due to their hydropedological specifics and high soil erosion risk. Soil heterogeneities can cause preferential and/or lateral flow on the entire hillslope resulting in the off-site movement of water, fertilizers and chemicals used in crop production. A study was conducted under controlled conditions in a laboratory with undisturbed soil cores (250 cm3), which were used to estimate the soil hydraulic properties (SHP) using HYPROP and WP4C devices, while undisturbed soil columns (diameter = 16 cm, length = 25 cm) were used for the evaluation of preferential flow pathways using potassium bromide and Brilliant Blue. Samples were excavated in triplicate from the hilltop, backslope and footslope regions within the inter-rows of a vineyard from a critical zone observatory, SUPREHILL, in Croatia in Dystric Luvic Stagnosol. The aim of this study was to determine if the erosion-affected hillslope position affected the physical, chemical and hydraulic properties of soil and to identify water flow and possible preferential flow using dye and bromide tracers. The results of the sensor measurements and estimated SHPs were in agreement, showing a faster leaching of the irrigated rainwater in the footslope column. The tracer experiments showed variability even in the columns taken from the same position on the hillslope, which can be linked to plant roots and soil fauna activity. Altogether, the results showed a deeper loose layer at the footslope as a consequence of the soil erosion, which then resulted in higher hydraulic conductivity and the leached mass of the bromide due to better soil structure and pore connectivity. Thus, due to significant differences in the leached mass of bromide, this research should be later expanded in field experiments to reveal the impact of surface runoff, subsurface preferential and lateral flow on a larger scale
Research on interdependence between specific rock cutting energy and specific drilling energy
No full textA method based on extensive laboratory and field measurements was developed to determine the dependence of specific rock cutting energy (SEc) on specific drilling energy (SEd) for machines with different operating and design characteristics and similar breaking mechanics. Laboratory measurements were performed on a linear rock cutting device and a laboratory drill, using a measurement system to measure electrical power and cutting forces using force/torque transducers. Field power consumption measurements were performed on a chainsaw cutting machine and a hydraulic rotary drill under real working conditions in the dimension stone quarries. The analysis of the measured results confirmed the strong dependence of the specific rock cutting energy on the specific drilling energy and confirmed that laboratory devices can be used to simulate actual rock cutting and drilling process. In addition, the results are applicable in the dimension stone exploration and exploitation phase in order to assess and reduce energy consumption by optimizing the operating parameters of the chain cutter and/or the hydraulic rotary drill
Investigation of hillslope vineyard soil water dynamics using field measurements and numerical modeling
No full textSoil heterogeneities can impact hillslope hydropedological processes (e.g., portioning between infiltration and runoff), creating a need for in-depth knowledge of processes governing water dynamics and redistribution. The presented study was conducted at the SUPREHILL Critical Zone Observatory (CZO) (hillslope vineyard) in 2021. A combination of field investigation (soil sampling and monitoring campaign) and numerical modeling with hydrological simulator HYDRUS-1D was used to explore the water dynamics in conjunction with data from a sensor network (soil water content (SWC) and soil-water potential (SWP) sensors), along the hillslope (hilltop, backslope, and footslope). Soil hydraulic properties (SHP) were estimated based on (i) pedotransfer functions (PTFs), (ii) undisturbed soil cores, and (iii) sensor network data, and tested in HYDRUS. Additionally, a model ensemble mean from HYDRUS simulations was calculated with PTFs. The highest agreement of simulated with observed SWC for 40 cm soil depth was found with the combination of laboratory and field data, with the lowest average MAE, RMSE and MAPE (0.02, 0.02, and 5.34%, respectively), and highest average R2 (0.93), while at 80 cm soil depth, PTF model ensemble performed better (MAE = 0.03, RMSE = 0.03, MAPE = 7.55%, R2 = 0.81) than other datasets. Field observations indicated that heterogeneity and spatial variability regarding soil parameters were present at the site. Over the hillslope, SWC acted in a heterogeneous manner, which was most pronounced during soil rewetting. Model results suggested that the incorporation of field data expands model performance and that the PTF model ensemble is a feasible option in the absence of laboratory data
Atlas karata klizišta projekta LandSlidePlan
No full textAtlas karata klizišta projekta LandSlidePlan sadrži konačne karte inventara i karte zoniranja podložnosti na klizanje za tri pilot područja u Gradu Zagrebu, Hrvatskom zagorju i Istri. Karte su izrađene u okviru projekta 'Razvoj metodologije procjene podložnosti na klizanje za planiranje namjene zemljišta primjenom LiDAR tehnologije' (HRZZ IP-2019-04-9900) financiran od Hrvatske zaklade za znanost.Karte inventara klizišta izrađene su interpretacijom morfometrijskih karata izvedenih iz LiDAR digitalnog modela terena visoke rezolucije. Karte zoniranja podložnosti na klizanje izrađene su primjenom metode slučajnih šuma iz različitih preduvjeta klizanja visoke rezolucije i karte inventara klizišta