Papers by Nediljka Gaurina-Međimurec
One of the critical factors in designing non-damaging fluids is obtaning surface bridging on the ... more One of the critical factors in designing non-damaging fluids is obtaning surface bridging on the formation face with minimum indepth solids penetration. This can be done by optimizing the particle size distribution of calcium carbonate as the bridging agent. The paper presents laboratory data from tests carried out on selected fluids which show the extent of the changes that occur in fluid filtration properties (spurt loss, PPT value and static filtration rate)when calcium carbonate with different PSD is used. The Permeability Plugging Aparatus and ceramic disks of different permeabilities were used to evaluate the filtration and spurt loss of selected fluids.
Effect of polymer swelling that was considered to be a problem, gives today a possibility, to com... more Effect of polymer swelling that was considered to be a problem, gives today a possibility, to complete wells that are a problem one for conventional packer setting and sealing. Polymers (rubbers) can swell in hydrocarbons or water based fluids as well. Several ways of application have been accepted. Mainly they are connected with open hole and sand screen completions in unconsolidated formations. The ability of changing the volume to more than several hundred percent, can help to avoid packer failure. When defining swelling packer elements it is important to determine their mechanical properties, swelling speed in various fluids, and stability (ageing tests). To implement home made products it was necessary to provide laboratory testing equipment for such purpose. The developed apparatus enables use of different fluids, temperature change up to known reservoir temperature, and pressure differential that element can withstand.
Differential-pressure pipe sticking occurs when a portion of the drill string becomes embedded in... more Differential-pressure pipe sticking occurs when a portion of the drill string becomes embedded in a filter cake that forms on the wall of a permeable formation during drilling. The dominant force is usually associated with a difference in pressures between the hydrostatic pressure of the mud and the pore pressure in the contact area, though adhesion and cohesion may also contribute some resistance to pipe movement. Some level of sticking occurs routinely in drilling operations and differential-pressure-pipe-sticking problems may not be totally prevented. These events only became problematic if the force required to pull the pipe free exceeds the pipe strength. If sticking does occur, several methods can be used for freeing the stuck pipe but the most common approach is to place a small volume of oil, or special spotting fluid in a wellbore annulus to free differentially stuck pipe. Spotting fluid reduces the stuck area and the forces of cohesion between the pipe and cake, and allowi...
Coiled tubing drilling applications are becoming more widely used because of their major advantag... more Coiled tubing drilling applications are becoming more widely used because of their major advantages over the conventional jointed pipe drilling methods. Some of the advantages are: – drilling and trip under pressure, – continous circulation while tripping, – slimhole and thru tubing capability, – small location footprint. Before using coiled tubing (CT) for drilling practice, serious engineering considerations have to be taken into account because of coiled tubing limitations such as: – small diameters, – limited reach in horizontal wells. – hydraulic limitations etc. Cuttings transport during drilling (either conventionally or with coiled tubing) has a major impact on the economics of the drilling process. Inefficient hole cleaning can lead to numerous problems such as stuck pipes, reduced weight on the bit and reduced rate of penetration, lost of circulation, additional costs because of adding additives in the drilling fluid, wasted time for wiper tripping etc. One of the major ch...
Large quantities of waste fluids (drilling mud, produced water, workover and completion fluids, f... more Large quantities of waste fluids (drilling mud, produced water, workover and completion fluids, fluids from processing units, etc.) and their associated wastes are created during everyday activities and they must be disposed of on an environmentally acceptable manner. Subsurface injection of waste fluids has proven to be an environmentally, technically and economically suitable method for the disposal of waste fluids generated during drilling oil and gas wells, and production of oil and gas. This paper describes the subsurface injection technology, the disposal formation characteristics, the waste disposal well design, the reserve mud pit closure technology used in Croatia, as well as proposes a solution for the future according to world experience.
Utjecaj nanočestica SiO 2 i TiO 2 na svojstva isplaka na bazi vode Effect of SiO 2 and TiO 2 nano... more Utjecaj nanočestica SiO 2 i TiO 2 na svojstva isplaka na bazi vode Effect of SiO 2 and TiO 2 nanoparticles on water-based muds properties Monika Miličević, univ.bacc.ing.petrol. Rudarsko-geološko-naftni fakultet, Sveučilište u Zagrebu
Utjecaj nanočestica SiO 2 i TiO 2 na svojstva isplaka na bazi vode Effect of SiO 2 and TiO 2 nano... more Utjecaj nanočestica SiO 2 i TiO 2 na svojstva isplaka na bazi vode Effect of SiO 2 and TiO 2 nanoparticles on water-based muds properties Monika Miličević, univ.bacc.ing.petrol. Rudarsko-geološko-naftni fakultet, Sveučilište u Zagrebu
UTJECAJ NANOČESTICA SiO2 I TiO2 NA SVOJSTVA ISPLAKA NA BAZI VODE EFFECT OF SiO2 AND TiO2 NANOPART... more UTJECAJ NANOČESTICA SiO2 I TiO2 NA SVOJSTVA ISPLAKA NA BAZI VODE EFFECT OF SiO2 AND TiO2 NANOPARTICLES ON WATER-BASED MUDS PROPERTIES Monika Miličević, univ.bacc.ing.petrol. Rudarsko-geološko-naftni fakultet, Sveučilište u Zagrebu Carla Ključarić, univ.bacc.ing.petrol. Rudarsko-geološko-naftni fakultet, Sveučilište u Zagrebu Sven Mijić, univ.bacc.ing.petrol. Rudarsko-geološko-naftni fakultet, Sveučilište u Zagrebu Petar Mijić, mag. ing. petrol., asistent Rudarsko-geološko-naftni fakultet, Sveučilište u Zagrebu Dr. sc. Nediljka Gaurina-Međimurec, redovita profesorica Rudarsko-geološko-naftni fakultet, Sveučilište u Zagrebu
Prof. dr. sc. Nediljka Gaurina-Međimurec, redovita profesorica Rudarsko-geološko-naftni fakultet,... more Prof. dr. sc. Nediljka Gaurina-Međimurec, redovita profesorica Rudarsko-geološko-naftni fakultet, Sveučilište u Zagrebu Doc. dr. sc. Borivoje Pašić, docent Rudarsko-geološko-naftni fakultet, Sveučilište u Zagrebu Petar Mijić, mag. ing. naft. rud., asistent Rudarsko-geološko-naftni fakultet, Sveučilište u Zagrebu Ključne riječi: gubitak isplake, zone gubljenja isplake, isplaka, ekvivalentna gustoća isplake u cirkulaciji, materijali za zatvaranje zona gubljenja
Temeljni cilj ove agroekoloske analize je utvrditi trenutno (nulto) stanje kvalitete tla, vode, z... more Temeljni cilj ove agroekoloske analize je utvrditi trenutno (nulto) stanje kvalitete tla, vode, zraka i sumskih ekosustava prije pocetka provođenja EOR (Enhanced Oil Recovery) projekta odnosno povecanja iscrpka ugljikovodika iz starih naftnih ležista. Navedena metoda koristi CO2 izdvojen iz prirodnog plina pridobivenoga na poljima Podravine (Molve, Kalinovac, Stari Gradac). Nakon dehidracije i komprimiranja CO2 se transportira cjevovodom do lokacije objekata frakcionacije Ivanic Grad gdje se nakon komprimiranja i pothlađivanja utiskuje u polja Žutica i Ivanic. Uz primarni cilj, proizvodnju dodatnih kolicina ugljikovodika, projekt znacajno doprinosi smanjenju emisija staklenickih plinova. Trenutno se CO2 ispusta u atmosferu, a EOR projektom utisnut ce se u ležista navedenih polja.
Applied sciences, Mar 23, 2023
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
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Papers by Nediljka Gaurina-Međimurec