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Usporedba zvučnih karotažnih mjerenja sondom na kabelu i tijekom bušenja : završni rad
No full textZvučna karotaža pruža neophodne informacije o fizikalnim svojstvima nabušenih stijena te fluida koji se u njima nalaze. Jedno je od osnovnih mjerenja korištenih za utvrđivanje prisutnosti ugljikovodika i omogućavanja njihove učinkovite i sigurne proizvodnje. Princip mjerenja je mjerenje vremena prolaska elastičnog vala između odašiljača i prijemnika na sondi. Zvučna karotaža može se provoditi na dva načina, mjerenjem pomoću sonde spuštene na kabelu ili mjerenjem tijekom bušenja (LWD). U ovome radu prikazane su razlike između građe alata i uvjeta mjerenja ovih dviju metoda, kao i njihove prednosti i nedostaci. Usporedbom podataka o intervalnim brzinama dobiven je uvid u njihovu kvalitetu i preciznost. Iako zvučna karotaža tijekom bušenje ima manji opseg mjerenja pokazala su se mala odstupanja, uglavnom ovisna o uvjetima unutar bušotine. Može se reći da LWD mjerenja imaju prednost tijekom izrade kanala bušotine, prije potencijalnih oštećenja ili prodora filtrata isplake, međutim mjerenja sondom na kabelu pokazuju ipak nešto kvalitetnije podatke zahvaljujući povoljnim uvjetima u bušotini tijekom mjerenja
Usporedba interpretacije seizmičkih refrakcijskih podataka pomoću softvera otvorenog koda i komercijalnog softvera : završni rad
No full textU ovom završnom radu cilj je analizirati razlike u korištenju i rezultatima komercijalnog sofvera i softvera otvorenog koda za obradu podataka dobivene metodom refrakcijske seizmike. Nakon uvoda opisana je metoda refrakcijske seizmike gdje je generalno opisano na čemu se ona temelji, za što se koristi te metode inverzije koje se koriste pri obradi. Za primjer principa rada korišteni su podaci duž dva profila koji su uneseni u oba softvera. Nadalje, u koracima je opisan princip rada u Refrapy-u pa u Rayfract-u, na koji način se aktivira softver, učitavaju podaci, spremaju datoteke i provodi inverzija. U oba softvera se provela inverzija i dobiveni su modeli koji su interpretirani i uspoređeni kako bi se vidjele razlike i u njima. Za kraj je napisana diskusija u kojoj se govori o prednostima i nedostatcima u korištenju pojedinog softvera
Studija slučaja sanacije brownfield područja u priobalju : završni rad
No full textBrownfield područja su zemljišta ili nekretnine koje su napuštene, a prethodno korištene u vojne, komercijalne ili industrijske svrhe, sada su izvan funkcije i vrlo često zagađene. Glavni razlozi nastanka takvih područja su skupa i dugotrajna sanacija i složena obnova radi prisustva opasnih tvari. U odnosu na ostatak svijeta obnova i važnost brownfield područja u Hrvatskoj je manje izražena no u posljednje vrijeme vidljiv je porast interesa za takve lokacije. Razlog tome je nedostatak strateških planova i jasnih strategija, neriješenih vlasničkih odnosa koji su često veoma složeni te financijskih restrikcija. Svi spomenuti izazovi su ilustrirani na primjeru bivše tvornice „Dalmacija“ u Dugom Ratu u kojoj su se proizvodile ferolegure, cijanamid i kalcijev karbid, na čijem području nakon gašenja zaostaju znatne količine otpada kako na tlu tako i pod morem. Ključni aspekti nužni za revitalizaciju su rješavanje imovinsko pravnih odnosa, provedba detaljnih istraživanja tla, mora, zraka, podzemnih voda, potpuna sanacija područja, te planiranje isplativost projekta
Deep-well waste disposal : technological, regulatory and environmental challenges and opportunities : master's thesis
No full textKroz pregled povijesnog razvoja tehnologije, regulative, te rizika povezanih s utiskivanjem, rad istražuje učinkovitost ove metode za smanjenje utjecaja otpada na okoliš. Detaljno su prikazani zakonski okviri u SAD-u i EU, kao i tehnički izazovi u odabiru lokacija i održavanju mehaničkog integriteta bušotina. Unatoč rizicima poput potencijalne kontaminacije podzemnih voda, pravilno regulirane i nadzirane tehnike utiskivanja otpada mogu igrati ključnu ulogu u održivom zbrinjavanju otpada i smanjenju štetnih emisija. Osim toga, razmatra se tehnologija hvatanja i skladištenja ugljikovog dioksida (CCS) kao važan alat u smanjenju emisija stakleničkih plinova, s posebnim primjerima iz europskih projekata poput norveškog Sleipnera.Through an analysis of the historical development of technology, regulation, and risks associated with deep well injection, this paper covers the effectiveness of this method for reducing the impact of waste on the environment. The legal frameworks in the USA and the EU are presented in detail, as well as the technical challenges in selecting locations and maintaining the mechanical integrity of wells. Despite risks such as potential groundwater contamination, properly regulated and monitored waste injection techniques can play a key role in sustainable waste management and reduction of harmful emissions. In addition, carbon capture and storage (CCS) technology is considered as an important tool in reducing greenhouse gas emissions, with specific examples from European projects such as Norway's Sleipner
Classification of lava in Iceland using Sentinel-2 multispectral images : master's thesis
No full textCilj ovog diplomskog rada je korištenje daljinskih istraživanja u svrhu klasificiranja lave na Islandu pomoću QGIS alata i njegovih dodataka. Kao posljedica niza erupcija vulkana krajem listopada 2023. godine u narednim mjesecima Island je iskusio niz zastrašujućih i opasnih situacija u kojima su bile potrebne mjere evakuacije. Korištenjem Sentinel-2 satelita preuzeta su dva seta podataka od kojih jedan predstavlja područje prije erupcije, a drugi poslije erupcije. Upotrebom SCP plugina za QGIS softver napravljeni su treninzi za nadziranu klasifikaciju prije i poslije erupcije lave. Algoritmi po kojima je rađena klasifikacija su maximum likelihood (maksimalna vjerojatnost), minumum distance (minimalna udaljenost) i spectral angle mapping (spektralno kutno kartiranje), sva tri algoritma korištena su na četiri treninga i uz promatranje samog njihovog rada, uspoređena je i ovisnost kvalitete treninga o dobivenim rezultatima.The purpose of this thesis is to classify lava in Iceland using remote sensing and GIS tools and plugins. In the last months Iceland experienced multiple frightening and dangerous situations in which evacuation measures were necessary as a result of a series of volcanic eruptions at the end of October 2023. Two sets of Sentinel-2 satellite data were downloaded, one which represents area of interest before eruption and the other after. Using the SCP plugin for QGIS software, four training data sets were made to use for supervised classification on examples before and after lava. Algorithms used for the classification are maximum likelihood, minimum distance and spectral angle mapping, all three algorithms were trained on all four training sets. In the end, the quality analysis was performed to determine which algorithm is the most suitable
Influence of mandarin peel powder on the filtration and rheological properties of complex water-based drilling muds : master's thesis
No full textUloge isplake pri izradi kanala bušotine su brojne pri čemu je kontrola filtracijskih i reoloških svojstava od ključne važnosti. Aditivi se dodaju u isplaku radi poboljšavanja svojstava. Otpad u naftnom rudarstvu potrebno je ispravno odlagati, te aditivi kao dio isplake često budu štetni za okoliš. U današnje vrijeme provode se brojna istraživanja kako bi se biorazgradivi aditivi implementirali u naftnu industriju. U ovom radu ispitivane su isplake u kojima je kao aditiv korišten prah kore mandarine (PKM) veličine čestica do 0,1 mm. U dvije osnovne isplake na bazi vode, složenog sastava, dodan je prah kore mandarine kao aditiv u različitim koncentracijama. Postupnom promjenom koncentracije karboksimetilceluloze kao glavnog aditiva za kontrolu filtracijskih svojstava i dodavanjem praha kore mandarine kao supstituciju za karboksimetilcelulozu, dobivene su isplake čija su svojstva podvrgnuta ispitivanjima. Rezultati su pokazali da se dodavanjem praha kore mandarine kao aditiva u kombinaciji s karboksimetilcelulozom smanjuje filtracija, dok pri dodavanju 15 g praha kore mandarine u osnovnu isplaku A, u kojoj je koncentracija karboksimetilceluloze 5 g/L, dolazi do smanjenja volumena filtrata za čak 29 % u odnosu na osnovnu isplaku A. Dodavanjem 30 g/L praha kore mandarine u osnovnu isplaku B (drukčijeg sastava s koncentracijom karboksimetilceluloze od 2 g/L) dolazi također do smanjenja volumena filtrata za 29 % u odnosu na osnovnu isplaku B no dolazi i do izraženih promjena reoloških svojstava. Zaključeno je kako prah kore mandarine u različitim koncentracijama utječe na reološka i filtracijska svojstva složenih isplaka, te su najbolji rezultati vidljivi pri kombiniranju standardnog aditiva za kontrolu filtracije karboksimetilceluloze u koncentraciji od 5 g/L i optimalne koncentracije praha kore mandarine veličine čestica do 0,1 mm od 15 g/L. Prah kore mandarine, uz dodatna ispitivanja, ima budućnost kao isplačni aditiv u naftnoj industriji.The roles of drilling fluids are numerous in the drilling operations, where the control of filtration and rheological properties is of key importance. Additives are added to drilling fluids to improve properties. Waste in oil industry must be disposed of properly, and additives as part of the drilling fluids are often harmful to the environment. Nowadays, numerous researches are being carried out in order to implement biodegradable additives in the oil industry. In this paper, drilling fluids were examined in which tangerine peel powder with a particle size of up to 0,1 mm was used as an additive. In two basic water-based drilling fluids, with a complex composition, mandarin peel powder was added as an additive in different concentrations. By gradually changing the concentration of carboxymethylcellulose as the main additive for controling filtration properties and adding mandarin peel powder as a substitution for carboxymethylcellulose, drilling fluids were obtained whose properties were subjected to tests. The results showed that the addition of mandarin peel powder as an additive in combination with carboxymethylcellulose reduces filtration, while adding 15 g of mandarin peel powder in basic drilling fluid A, in which the concentration of carboxymethylcellulose is 5 g/L, results in a decrease in filtrate volume by as much as 29 % compared to basic drilling fluid A. Adding 30 g/L of mandarin peel powder to basic drilling fluid B (of a different composition with a concentration of carboxymethylcellulose 2 g/L) also resultrs in a 29 % decrease in the filtrate volume compared to basic drilling fluid B, but significant changes in rheological properties also occur. It was concluded that mandarin peel powder in different concentrations affects the rheological and filtration properties of the complex drilling fluids, and the best results are visible when combining the standard carboxymethylcellulose filtration control additive in a concentration of 5 g/L and the optimal concentration of mandarin peel powder with particle size up to 0.1 mm of 15 g/L. Mandarin peel powder, with additional tests, has a future as a drilling fluid additive in the oil industry
Thermodynamic parameterization of carbon dioxide in the process of its permanent storage in water-saturated reservoirs at subcritical pressure : master's thesis
No full textOvaj rad prikazuje cjeloviti spregnuti model za termodinamičku parametrizaciju ugljikovog dioksida u procesu njegovog trajnog zbrinjavanja u vodom zasićena iscrpljena plinska ležišta pri potkritičnom tlaku. Utiskivanje u ležišta pri potkritičnom tlaku mogu zbog naglog pada tlaka u perforacijama i pribušotinskoj zoni dovesti do stvaranja hidrata ili smrzavanja ležišne vode uslijed Joule-Thomsonovog efekta. Zbog toga je potrebno provesti pripremu CO2 korištenjem površinske opreme u vidu povećanja tlaka radi ostvarivanja protoka i njegovog zagrijavanja. Proračun je proveden na jednom hipotetskom primjeru i rezultati pokazuju da model daje kvalitativno očekivana rješenja u smislu potrebne količine rada koja za transport CO2 cjevovodima iznosi iznad 150 kJ/kg, uz specifično odvedenu toplinu u iznosu od -200 kJ/kg, a za pumpanje CO2 prije utiskivanja oko 15 kJ/kg. S druge strane, zagrijavanje CO2 pri utiskivanju treba provesti sa specifičnom potrošnjom topline u iznosu od 250 kJ/kg.This paper presents a complete coupled model for the thermodynamic parameterization of carbon dioxide in the process of its permanent disposal in watersaturated depleted gas reservoirs at subcritical pressure. Pressing into reservoirs at subcritical pressure can lead to the formation of hydrates or icing of reservoir water due to a sudden drop in pressure in the perforations and near-well zone due to the Joule-Thomson effect. For this reason, it is necessary to carry out the preparation of CO2 using surface equipment in the form of increasing the pressure in order to achieve the flow and its heating. The calculation was carried out on a hypothetical example and the results show that the model provides qualitatively expected solutions in terms of the required amount of specific work, which for transporting CO2 through pipelines is over 150 kJ/kg with specific cooling at around –200 kJ/kg, and for pumping CO2 prior to injection around 15 kJ/kg. On the other hand, the heating of CO2 during pressing should be carried out with a specific heat consumption in the amount of 250 kJ/kg
Određivanje rasprostiranja sedimenata dna jezera na temelju podataka podvodne električne tomografije
No full textElectrical resistivity tomography (ERT) in an aquatic environment is usually measured using two basic systems. One system uses floating electrodes, which is usually applied in shallow water, and the other uses underwater cables with integrated electrodes, which is often carried out as a mobile system. The aim of this research was to test an underwater ERT measurement with floating cables on the water surface, but with electrodes submerged at the water bottom. This type of cable spread makes it possible to lay all the electrodes vertically to the bottom without the distance between them being reduced by the uneven topography and various underwater obstacles. Prior to the field survey that was conducted in a 40 m – deep lake, the response of common electrode arrays was tested using synthetic models. Two models were used that correspond to the geological condition in the field, higher resistivity bodies in a lower resistivity environment and a model with inverse relationship of resistivity to the first one. The Wenner Schlumberger and dipole-dipole arrays resolved the resistivity range, size and shape of the bodies very well and were therefore used in the field. The field data quality was very good and it was shown that ERT measurements in freshwater depths of more than 40 metres can provide very good results. As expected from the modelling, the dipole-dipole array led to a high-resolution resistivity model that enabled the characterisation of the lakebed sediments.Prilikom mjerenja električnom tomografijom (ERT) u vodenome okolišu najčešće se primjenjuju dva osnovna sustava. Prvi sustav koristi se elektrodama na površini i obično se primjenjuje u vodi male dubine, a drugi sustav koristi se podvodnim kabelima s integriranim elektrodama, koji se često izvodi kao mobilni sustav. Cilj ovoga istraživanja bio je testirati podvodno ERT mjerenje s plutajućim kabelima na površini vode, ali elektrodama uronjenim do dna. Prije samoga terenskog istraživanja koje je provedeno u jezeru dubine oko 40 m testirali smo odziv najčešće korištenih elektrodnih rasporeda postupkom modeliranja. Korištena su dva modela koja odgovaraju geološkim uvjetima na terenu: blokovi veće električne otpornosti u sredini niže otpornosti i model s obrnutim odnosom otpornosti. Rezultati pokazuju da dipolni i Wenner-Schlumbergerov elektrodni raspored daju odličan odziv u smislu raspona otpornosti, veličine i oblika blokova i stoga su korišteni prilikom testiranja u terenskim uvjetima. Mjerenjem su dobiveni podatci vrlo dobre kvalitete te se pokazalo da ovakva ERT mjerenja mogu dati vrlo dobre rezultate u slatkovodnim okolišima s dubinama većim od 40 metara. Kao što su pokazali i rezultati modeliranja, dipolni elektrodni raspored dao je model otpornosti visoke rezolucije koji je omogućio karakterizaciju sedimenata jezerskoga dna
The effect of operating variables on the performance of column flotation of silica sand
No full textThis paper presents the results of a study performed on silica sand samples to determine the effect of operating parameters (collector type and dosage, solids content in the pulp, pulp pH and air flow rate) on the concentrate grade and mass recovery in laboratory-scale column flotation. Through the analysis of variance (ANOVA), it was determined that the pulp pH had a significant impact on all four of the observed grade parameters (mass contents of SiO2, Al2O3, Fe2O3 and TiO2 in the concentrate). Air flow rate had a significant impact on the mass contents of SiO2 and Al2O3. The solids content in the pulp only significantly affected the mass content of Fe2O3. The mass recovery was significantly influenced by the pulp pH, with a high level of significance (p-value (p) = 0.002917), as well as by the air flow rate (p = 0.010285). On the basis of a model of the relationship between the respective grade parameters and tested operating variables, it was determined that with the use of the Aeromine 3030C collector (at a dosage of 500 g/t) the highest-grade concentrate regarding the mass contents of SiO2, Al2O3 and TiO2 was achieved with a pulp pH within a range from 2.4 to 3 and an air flow rate above 26 L/h. The lowest mass content of Fe2O3 in the concentrate was achieved at a pulp pH in a range from 2.2 to 2.8 and a solids content in the pulp between 2.0% and 3.5%
From traditional extrapolation to neural networks: Time-depth relationship innovations in the subsurface characterization of Drava Basin, Pannonian Super Basin
No full textThe estimation of time-to-depth relationships can prove challenging in regions with rare acoustic logs. This study focuses on the eastern part of the Drava Basin in north Croatia, chosen as a mature hydrocarbon exploration area with abundant geophysical and well data. As only a small portion of wells have well log measurements or seismic profiling performed, a time-to-depth extrapolation is often performed, which potentially results in the erroneous placement of well log markers in the time domain and affects the interpretation of seismic sections or volumes. This study proposes a novel methodology for predicting two-way travel time values in wells without vertical seismic profiling or acoustic logging. This research evaluates the parameters for the characterization of the velocity distribution in the subsurface and the efficiency of artificial neural networks versus conventional methods for this task. The constructed artificial neural network model has a correlation coefficient above 0.99 for the training, testing, and validation datasets, with a mean absolute error of approximately 25 milliseconds for each network. Artificial neural networks proved to have a lesser error in predicting the two-way time and are not sensitive to outlier values