Impact of carbon dioxide on Ivanić oilfield in tertiary oil recovery phase

Godišnja proizvodnja nafte u Hrvatskoj s više od 30 naftnih polja je nešto veća od 500 000 tona. Tijekom proteklih 50 godina iz naftnih ležišta u Hrvatskoj ostvaren je prosječan iscrpak nafte od 32,6% utvrđenih rezervi nafte. Sadašnja cijena nafte na svjetskom tržištu potencira primjenu tercijarnih metoda povećanja iscrpka nafte. Ukoliko se iz postojećih ležišta nafte u Hrvatskoj uz te metode poveća iscrpak nafte za 3%, to dovodi do povećanja godišnje proizvodnje od 15 000 tona nafte. U svjetskoj praksi sve zastupljenija je proizvodnja nafte tercijarnim metodama pri čemu utiskivanje ugljičnog dioksida u naftna ležišta ima najveću primjenu. Na temelju laboratorijskih ispitivanja primjene tercijarnih metoda povećanja iscrpka iz naftnih ležišta u Hrvatskoj utiskivanje ugljičnog dioksida je odabrano kao najpovoljnija metoda povećanja iscrpka nafte iz ležišta naftnog polja Ivanić. Tijekom utiskivanja ugljičnog dioksida u naftno ležište mijenja se njegovo agregatno stanje iz kapljevitog u plinsko ili pregrijano stanje. Mjereni podaci o ugljičnom dioksidu u laboratorijskim uvjetima i uvjetima utiskivanja u ležište nažalost odstupaju. S obzirom na to da su mjerenja u bušotinskim uvjetima skupa, a neki puta i tehnološki neizvediva, za poznavanje stanja ugljičnog dioksida u bušotinskim uvjetima uzimaju se različite aproksimacije uz upotrebu raznovrsnih jednadžbi stanja. Izmjereni podaci o faznom stanju ugljičnog dioksida u širokom rasponu p,T uvjeta tijekom njegova utiskivanja u ležišta naftnog polja Ivanić tijekom pilot projekta željeli su se aproksimirati nekom od brojnih jednadžbi stanja i ne mogu se na nekom drugom ležištu koristiti. Od brojnih kubičnih jednadžbi stanja odabrane su van der Waalsova, Redlich-Kwongova, Soave-Redlich-Kwongova, Peng-Robinsonova, Valderrama-Cisternasova, Patel-Tejina, Lawal-Lake- Silberbergova i Martin-Houova jednadžba. Nakon sveobuhvatne analize mjerenih i računatih vrijednosti u širokom rasponu p,T uvjeta preporučene su jednadžbe stanja za proračunavanje faznih stanja ugljičnog dioksida kod njegova utiskivanja u ležišta naftnog polja Ivanić.Current annual oil production in Croatia on more than 30 oilfields, amounts to a little more than 0.5 million t per year. In the last 50 years, the realized oil recovery factor from the oil reservoirs has on average amounted to 32.6% of original oil in place. The currently favourable oil price increases the need for higher oil recovery from existing oilfields through the implementation of tertiary oil recovery methods. As for Croatia, a 3% increase in the oil recovery factor from current oil reservoirs, obtained due to the implementation of tertiary oil recovery methods, increases annual oil production by 15 000 t. Although tertiary oil recovery methods (EOR methods) are becoming more common worldwide, carbon dioxide injection in oil reservoirs is the most implemented EOR method. Based on the laboratory test results of the applications of tertiary oil recovery methods on oil reservoirs in Croatia, the carbon dioxide injection process was chosen as an appropriate method for increasing oil production on the Ivanić oil field. During the injection stage, carbon dioxide changes the state of the matter from liquid to gaseous or supercritical state. Unfortunately, the measured carbon dioxide injection results and laboratory test results differ. In situ measurements are very expensive and sometimes impractical; therefore, various approximations are taken into account with numerous equations of state. The aim was to approximate an equation of state on the measured data, for a wide range of p,T conditions, during a pilot project of carbon dioxide injection on the Ivanić oilfield reservoir. Among numerous cubic equations of state, van der Waals, Redlich-Kwong, Soave-Redlich-Kwong, Peng-Robinson, Valderrama-Cisternas, Patel-Teja, Lawal-Lake- Silberberg and Matin and Hou equation of state. After comprehensive comparisons and analysis of the values measured and calculated for a wide range of p,T conditions during carbon dioxide injection on the Ivanić oilfield, some of equations of state were recommended for determinations carbon dioxide changes of state

GEOTEHNIČKI MODELI TEMELJENJA MOSTA MASLENICA

On the site of Maslenica bridge structural tectonic, geophysical and engineering geological investigations, geotechnical drilling and laboratory sample testings were performed. Maslenica anticline is characteristic for the investigated area. It is built from the limestone of Cretaceous age. The anticline has an asymmetrical form with the vergence of the axial plane towards the north. Reverse faults with recent activities are present. The recent activity was proved by the discovery of the broken stalactite with the displacement of 11 cm, whose age is 36000 years. On quite young stalactites (stalagmites) in the cave on the west side, no displacements were noticed. For the next period of 500 years the maximal possible displacement of 2.0 cm is foreseen. Smaller caves with the dimensions of 1 m3, were formed on the intersections of the reverse faults and greater joints. The canyon Novsko ždrilo was formed in the fault shear zone with tectonic transport to the right. According to the range of fracture, three characteristic types of rock masses were separated by engineering geological investigations. According to »Geomechanical classification« (RMR) the first type corresponds to II to III class, while the second type corresponds to IV class, and the third type corresponds to V class (mylonite). Because of the complexity of the terrain structure, original engineering geological bases of design have not enabled the direct application of the analysis of stress-strain behaviour. Because of that the simplified geotechnical models were done. They enabled the projecting of foundation in the rock mass and renewal of poor quality rock mass.Na lokaciji Masleničkog mosta urađena su strukturno-tektonska. geofizička i inženjerskogeološka istraživanja, istražna bušenja i laboratorijska ispitivanja uzoraka. Za istraživano područje karakteristična je Maslenička antiklinala. Izgrađena je od vapnenaca kredne starosti. Antiklinala ima asimetričan oblik s vergencijom osne ravnine prema sjeveru. Prisutni su reversni rasjedi s recentnom aktivnošću. Recentna aktivnost dokazana je nalazom presječene sige s pomakom od 11 cm, čija starost je 36000 god. Na sasvim mladim sigama u špilji na zapadnoj strani nisu uočeni pomaci. Za povratni period od 500 godina progno¬ziran je mogući maksimalni pomak veličine do 2,0 cm. Manje špilje dimenzija do 1 m3 nastale su na presjecištima reversnih rasjeda i većih pukotina. Kanjon Novsko ždrilo nastao je u zoni smicanja rasjeda s desnim tektonskim transportom. Prema stupnju razlomljenosti izdvojene su inženjerskogeološkim istraživanjem tri karakteristične sredine. Prema »Geomehaničkoj klasifikaciji« (RMR) prva sredina odgovara II, do III. klasi, druga sredina odgovara IV. klasi, a treča sredina odgovara V. klasi (milonit). Originalne inženjerskogeološke podloge nisu omogućile, zbog složenosti građe terena, direktnu primjenu u analizi odnosa naprezanja i deformacija. Zbog toga su izrađeni simplificirani geotehnički modeli. Oni su omogućili projektiranje temeljenja u stijenskoj masi i saniranja dijelova slabe kvalitete

Findings of bivalves in the Miocene of the Zrinska Gora Mt.

Dosadašnja istraživanja na području Zrinske gore ukazala su na specifičnosti životom bogatog okoliša srednjeg miocena na prostoru tadašnjeg centralnog dijela Paratethysa. Ovim je radom prikazan pronalazak fosilnih školjkaša iz badenskog razdoblja na području Zrinske gore. Također se pokušalo ukazati na njihove specifičnosti, poput izrazite veličine, koje su proizašle iz pogodnih uvjeta u okolišu u kojem su obitavali. Okoliš je bio relativno mirno suptropsko more puno hranjivih tvari, s mnoštvom raznolikih organizama. Među pregledanim uzorcima zabilježeni su rodovi Pecten?, Pholadomya i Ostrea, od tih rodova se rod Pholadomya rjeđe pronalazi u miocenskim naslagama sjeverne Hrvatske. Svaki zabilježeni pronalazak fosilnih organizama i intrepretacija njihovog okoliša značajne su, kako za paleogeografiju, tako i za paleoekologiju, te modernu ekologiju jer nam mogu ukazati na neke interakcije okoliša i organizama koje u prirodi možda ne bi bili uočeniPrevious investigations in the area of the Zrinska Gora Mt. have shown that environments were rich in various living forms during the Middle Miocene in the area that was then part of the Central Paratethys Sea. This paper reports about findings of fossil bivalves from Badenian stage in the area of the Zrinska Gora Mt. The paper focuses to show their specifics, such as pronounced size which is the result of the favorable environmental conditions. The environment was relatively still subtropical sea with sufficient amount of nutrients, full of various living forms. Analysed specimens include genera Pecten?, Pholadomya and Ostrea of which genera Pholadomya was rarely found in the Miocene deposits of Nothern Croatia. Every marked finding of fossils and their paleoenviroment interpretations is valuable not only for paleogeography, but also for modern ecology since they can give us clues on interactions between enviroment and organisms which may not have been observed otherwise

Evaluation of Advanced Safety Perimeter Systems for Kansas Temporary Work Zones

Every year approximately 120 workers die in work zones, with approximately 60 percent of them as a result of intrusion accidents. Temporary work zones have a critical safety gap due to the expense and time needed to deploy positive protection systems, allowing intrusions to occur more easily. In order to help address this gap, the two safety perimeter systems currently on the market, the Intellicone and the SonoBlaster, were evaluated for their applicability for temporary work zones in Kansas. The SonoBlaster is entirely mechanical, channelizer-mounted and produces an air-horn-like alarm when tipped over. The Intellicone is electronic, with sensors mounted on channelizers, which transmit a warning signal to a site alarm that produces an electronic auditory and visual alarm. Testing was conducted in two phases: closed-course testing and field testing. Closed-course testing evaluated the operational parameters of both systems, especially their alarm sound levels and sound distribution. The Intellicone was found to be relatively quieter, but more consistent in alarm sound level, while the SonoBlaster was found to be relatively louder, but with much greater variation. The activation angles for both systems were also tested, as well as the transmission distance and battery life of the Intellicone system. Field testing was conducted at four active work zones, ranging from local roads to an interstate highway. Both systems were deployed at each location and set off, allowing workers to experience alarm activations as if intrusion accidents had occurred. Following testing at each location, an oral survey was administered to the workers regarding their opinions on each system's effectiveness, suitability, and safety benefits. The majority of workers felt both safety perimeter systems were good and would be useful in helping address safety concerns from intrusion accidents. However, the sound volumes were perceived to be too low, with the Intellicone being too quiet and the SonoBlaster's sound being localized too far from where work was actually occurring in the work zone. Both systems showed great promise, as well as having worker acceptance. There were some minor difficulties: system setup was more difficult for the SonoBlaster, while the Intellicone had a few technical glitches. However, this research demonstrated that such safety perimeter systems have great potential to be successfully deployed to increase worker safety

Ispis digitalnih fotografija

Iako digitalna fotografija spada u novija tehnička dostignuća, kontinuirano povećanje njene kvalitete i smanjenja troškova razlog su sve veće dostupnosti i njezine primjene. Tema ovog završnog rada je ispis digitalnih fotografija u kojem je obuhvaćen cjelokupni proces ispisa, od prijenosa fotografije na računalo, formata za pohranu fotografija, računalne obrade, prostora boja, odabira pisača, tinte i papira. Pomoću kolorimetrijskih testova dokazuje se ovisnost kvalitete ispisa o izboru pisača i podloge na koju se ispisuje. Također se nastoji pomoću smjernica ukazati na koje aspekte je potrebno najviše obratiti pozornost da bi se dobio što kvalitetniji i vjerodostojniji ispis. Jedna od glavnih prednosti digitalne fotografije nad klasičnom je fleksibilnost i mogućnost obrade nakon što je ona snimljena. U kratkim se crtama objašnjavaju korisni alati pri računalnoj obradi fotografija koji značajno utječu na sam izgled i ispis fotografije. Nabrojani su mnogi problemi koji se mogu javljati prilikom ispisa poput odabira krivog formata, rezolucije, balansa boja, mutne slike itd. Uz svaki problem navedeno je rješenje ili način kako ga izbjeći

Analiza materijala valjaka za mjerenje kočne sile

U ovom radu objašnjeno je čemu služe valjci za ispitivanje kočne sile te način na koji se mjeri sila kočenja i uvjeti koji trebaju biti ispunjeni. Nakon određenog vremena eksploatacije samih valjaka dolazi do otpadanja prevlake te takvi valjci više nisu dobri za upotrebu i daju pogrešne rezultate.Prevlaka je potrebna na valjcima iz razloga što ona osigurava dovoljno visok faktor trenja između pneumatika i valjka koji po zakonu ne smije biti manji od 0,5. Otpadanjem dijelova prevlake sa valjka javljaju se područja gdje se postižu niski faktori trenja, te time ni izmjerena kočna sila nije dosljedna i pojavljuju se skokovi u mjerenju. U eksperimentalnom dijelu rada otkriven je uzrok otpadanja prevlake te analizirani uvjeti rada i mehanizmi trošenja prevlake. Navedeni su primjeri obnove od strane dvije tvrtke, te ponuđena rješenja i načini obnove kako bi se osigurala dogotrajnost prevlake i time produljilo vrijeme eksploatacije samih valjaka

Extra-curricular exposure: sources, types and impacts

In this thesis, we tried to answer the questions concerning extra-curricular exposure, focusing primarily on the formal extra-curricular exposure, namely private lessons and private language schools. In order to do that, we conducted a study which enlightened this poorly researched area. The main issues we tried to address regarded the potential differences between urban and rural contexts, motivation and its connection to the extra-curricular exposure, formal and informal. However, we primarily focused on the differences between private lessons and private language schools in terms of teachers, materials used, motivation for choosing one type over the other, and the influence of formal extra-curricular types of exposure on the grade. Our findings suggest that there was a difference between pupils from urban and rural contexts. Families from rural context had a lower socioeconomic status which implies a lower level of education. Pupils from urban contexts had better grades, they reported being more motivated for learning English, and they were more exposed to informal media contents in comparison to their peers from rural contexts. They were more prone to attend private language schools, with the aim of improving the knowledge of language, not the grade. On the other hand, pupils from rural contexts preferred private lessons over private language schools, since they aimed more at improving the grade. Comparing private lessons and private language schools, our study showed that private lessons were more often taken with the aim to improve the school grade, which they managed to do, while private language schools were more often attended with the aim of improving the knowledge of language by pupils with mostly excellent grades. Consequently, private language schools were attended for a longer period of time and more regularly. Teachers in Extra-curricular exposure: sources, types and impacts Kristina Novosel private lessons were in some cases less qualified than their colleagues in private language schools and the percentage of communication in English was lower in private lessons. All in all, it should be noted that we tried to make a sound study covering a vast, and in terms of research, mostly unexplored area. Further, more detailed research based on the guidelines we have laid out could bring more exciting findings

"Beta pung sasando untuk dunia" : innovation and creativity as identity negotiators among sasando biola players in Indonesia

Sasando biola is a diatonic tube zither made of bamboo with an external resonator, haik, with the number of strings ranging from 24 to 48. Nowadays widely recognized as a symbol of the Nusa Tenggara Timur province in Indonesia, sasando belongs to the traditions of the island of Rote, and Kupang in West Timor. This research stems from my experience of playing in Nusa Tuak, a band of combo musicians and sasando players who regularly performed in Yogyakarta and across Java, and the experience I gained there shaped the research in its methodology and inquiry. For the field research I conducted from November 2016 to June 2018 in Yogyakarta, and in January 2018 in Kupang, I opted for performance practice-based methodology. Actornetwork theory is applied through recognizing the actors which are relevant for my interlocutors, and which relate to each other to form a network. The chapters are organized in a manner which follows the recognized actors: firstly, I examine the history and then proceed with anatomy of the instrument, playing techniques, tuning, current performance and instrument-making practices. Accompanying practices related to the safeguarding, such as transmission of knowledge and the role of sasando in tourist promotion of Kupang are examined as well. Through all the mentioned categories, sasando is a symbol and a medium of expressing the identity of both individuals and the local community. Creativity and innovation of each sasando player and/or maker contribute to the development of sasando and its symbolic and medial role. The thesis also includes an analysis of performance practice of Ofa Langga, a song from Rote which became widely recognized as a local anthem, and a YouTube playlist with these and other performances which I gathered in Kupang.Sasando biola je dijatonska cjevasta citra izrađena od bambusa, s vanjskim rezonantnim tijelom (haik) te 24 do 48 žica. Diljem Indonezije, danas je sasando prepoznat kao simbol provincije Nusa Tenggara Timur, iako izvorno pripada tradicijama otoka Rotea i Kupanga na Zapadnom Timoru. Moje istraživanje proizlazi iz iskustva sviranja u bendu Nusa Tuak, koji je redovno nastupao u Yogyakarti i diljem Jave. Iskustvo koje sam stekla u bendu utjecalo je na metodologiju istraživanja kojeg sam provela od studenog 2016. do lipnja 2018. godine u Yogyakarti, a tijekom siječnja 2018. u Kupangu, pa se tako istraživanje i u Kupangu prvenstveno temeljilo na izvedbenoj praksi. Takozvanu actor-network theory primijenila sam kako bih prepoznala čimbenike (actors) koji utječu na glazbovanje sugovornika te sam prema njima oblikovala izlaganje u ovom diplomskom radu. Počevši od povijesti i razvoja instrumenta, u sljedećim poglavljima propitujem tehnike sviranja, ugodbe, trenutnu izvedbenu praksu i praksu izrade instrumenta, kao i one prakse vezane uz očuvanje baštine, poput prijenosa znanja i uloge sasanda u turističkoj promociji grada Kupanga. U svim spomenutim kategorijama, sasando je i simbol i medij izražavanja i pregovaranja identiteta, kako pojedinca, tako i identiteta lokalne zajednice. Pritom kreativnost i inovativnost svakog svirača i/ili graditelja sasanda doprinose razvoju instrumenta i njegovoj simboličnoj i medijalnoj ulozi. Ovaj diplomski rad također uključuje analizu izvedbene prakse pjesme Ofa Langga, koja potječe s Rotea i koja je danas prepoznata kao svojevrsna lokalna himna te listu video-snimki, dostupnih putem Youtubea, koje sam snimila u Kupangu