Majstorska Cesta is a historical road along Velebit Mt., NW of Sveti Rok, preserved in its original state since opening in 1832 and therefore added to the cultural heritage list of the Republic of ...Croatia in 2007. The road passes through sedimentary rocks ranging in age from Upper Carboniferous to Upper Paleogene, i.e. from 315 Ma until approx. 25 Ma old rocks (a time span of 290 Ma). These are mostly well exposed limestones and dolomites, sporadically clastics. Such rocks build up not only Velebit Mt., but also the entire Karst Dinarides. As such, they represent a unique natural museum important not only for the Croatian landscape, but also for all countries with shallow marine carbonates in the Mediterranean Region and wider, i.e. areas of Mexico, the Caribbean, along mountains like the Atlas, the Pyreneans, the Alps, the Carpathians, the Dinarides, the Helenides, the Pontides, the Taurides, the Iranides and the Himalayas. The most important geological feature is a section from Mali Alan Saddle to Tulové Grede Ridge. It is a continuous section along the Jurassic carbonates, typical for the Karst Dinarides, of stratigraphic period from Hettangian to Middle Tithonian (201.3-148 Ma), comprising the typical (index) fossils and complete geological rock sections, including contact between Jurassic and Triassic rocks. The authors have researched Velebit Mt. since 1962 until recent times, and thus recognize the necessity to preserve the described Jurassic rock outcrops. They describe the geology of Majstorska Cesta from Sv. Rok to Obrovac.
Full text
Available for:
CEKLJ, NUK, ODKLJ, UL, UM, UPUK
(1) The ancient Paratethys Sea was a spacious inland salt-water basin, extending from the Alps, over Central Europe, to Central Asia. The southwestern part of its central area, the Croatian part of ...the Pannonian Basin System (CPBS), is generally known for shallow-water deposition and biota. The main purpose of this paper is to emphasize the significance of its less widespread deeper-water deposits in environmental and applied geology. (2) The authors consulted the previously published data, combined with their own results, obtained from the paleontological and sedimentological research, seismic stratigraphy and well-log analyses. (3) During our research in the CPBS, we noticed the connection between the tectonic structures and deep marine canyons and depressions within the Paratethyan shallows. Such structures can be recognized on well-logs and seismic or surface outcrops. They are situated along the faults, and deposits are characterized by the domination of pelagic over the benthic biota, sometimes with visible selective dissolution of aragonite/calcite tests. (4) Studied sedimentary sequences from these structures proved to be a precious source of data on the transgressive-regressive cycles, ancient migrations, modes of deposition and hydrocarbon formation during the Miocene Epoch in the CPBS.
Full text
Available for:
IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Kao povijesna velebitska prometnica Majstorska cesta uvrštena je na popis kulturnih dobara Republike Hrvatske 2007. godine, ponajprije stoga što je od izgradnje i puštanja u promet 1832. godine do ...danas očuvana u izvornoj trasi od Obrovca do lokaliteta Paljenik na sjeverozapadnome kraju mjesta Sveti Rok. Cesta leži na sedimentnim stijenama stratigrafskoga raspona od gornjega karbona do gornjega paleogena ili od 315 milijuna godina do oko 25 milijuna godina prije današnjice. To je raspon od 290 milijuna godina. Uglavnom su to izvrsno otkriveni vapnenci i dolomiti, a dijelom i klastične naslage. Spomenuti izdanci čine jedinstvenu reprezentativnu i znanstveno važnu prirodnu vrijednost u Hrvatskoj i na svjetskoj razini. Izgrađuju ne samo Velebit nego i sve karbonatne stijene krških Dinarida i kao takve jedinstven su prirodni geološki muzej važan kako za hrvatsko ozemlje, tako i za područja izgrađena od plitkomorskih karbonatnih stijena Sredozemlja u širemu geološkom smislu, tj. od Meksika i Kariba preko gorskih lanaca Atlasa, Pireneja, Alpa, Karpata, Dinarida, Helenida, Pontida, Taurida, Iranida do Himalaja. Najvažnija geološka znamenitost jest profil od prijevoja Mali Alan do Tulovih greda. Radi se o kontinuiranome profilu kroz jurske karbonatne stijene, tipskome za čitave krške Dinaride, u stratigrafskome rasponu od hetangija do sredine titona (raspon geološke starosti od 201,3 do oko 148 milijuna godina prije sadašnjosti), uključujući provodne fosile i kompletan stratigrafski slijed naslaga (stijena) te uvid u dodir jurskih sa starijim, trijaskim naslagama. Kao višedesetljetni istraživači Velebita (od 1962. godine do danas) željeli bismo upozoriti na potrebu zaštite spomenutih izdanaka stijena i jurske starosti. Geologija Majstorske ceste opisana je smjerom od Svetoga Roka prema Obrovcu.
Full text
Available for:
CEKLJ, NUK, ODKLJ, UL, UM, UPUK
Geological probability calculation was applied to the Northern Croatian Neogene deposits in the western Sava Depression. Structures “A” and “B” (with sandstone hydrocarbon reservoirs inside the ...Kloštar Ivanić Formation, Upper Miocene) were analyzed using two different Probability of Success (POS) methodologies. The classical POS approach showed that, in such play and wider areas of selected two structures, the probability for discovering the new HC reservoirs is 42.18%. This is valid for minimum of 500,000 m
3
of geological reserves. The modified POS approach has been used for calculation of waterflooding efficiency in selected structures “A” and “B.” The probability value of 56.25% indicates that future flooding would result in increased recovery.
Full text
Available for:
EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
U radu je prikazano istraživanje u podmorju sjevernog Jadrana i priobalja južne Dalmacije unutar naslaga pliocena, pleistocena i holocena. Njime su opisane postojeće litostratigrafske jedinice u ...taložinama rijeke Po u Hrvatskoj i određene takve jedinice u prostoru taloženja rijeke Neretve. Oba taložna prostora bila su pod utjecajem promjena razina mora, posebice tijekom kvartara, što se znatno odrazilo u smanjivanju dubine mora i povećanju površine kopna tijekom oledaba, posebice u sjevernom Jadranu. U hrvatskom dijelu Padske depresije navedene su dvije formacije – Istra (pliocen) i Ivana (pleistocen, holocen). U formaciji Ivana opisana su tri člana, poimence Anamarija, Katarina i Izabela. Dalje prema jugu, u priobalju južne Dalmacije, imenovana je nova formacija Neretvanski kanal (za taložine pliocena, pleistocena i holocena). Ona je zatim podijeljena u pijeske Neretva (koji mogu biti ekvivalent i cijele formacije) te član Malostonski zaljev (kvartarne starosti). Isključivo pliocenski tipski litotip nije opisan.
Full text
Available for:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The semivariogram and the ordinary kriging analyses of porosity data from the Sava Depression (Northern Croatia), are presented relative to the Croatian part of the Pannonian Basin system. The data ...are taken from hydrocarbon reservoirs of the Lower Pontian (Upper Miocene) age, which belong to the Kloštar Ivanić Formation. The original datasets had been jack-knifed with the purpose of re-sampling and calculating the more reliable semivariograms. The results showed that such improvements can assist in the interpolation of more reliable maps. Both sets, made by the original and re-sampled data, need to be compared using geological recognition of isoline’s shapes (such as “bull-eye” or “butterfly” effects) as well as cross-validation results. This comparison made it possible to select the most appropriate porosity interpolation.
Full text
Available for:
IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Interpolation is a procedure that depends on the spatial and/or statistical properties of the analysed variable(s). It is a particularly challenging task for small datasets, such as in those with ...less than 20 points of data. This problem is common in subsurface geological mapping, i.e., in cases where the data is taken solely from wells. Successful solutions of such mapping problems depend on interpolation methods designed primarily for small datasets and the datasets themselves. Here, we compare two methods, Inverse Distance Weighting and the Modified Shepard’s Method, and apply them to three variables (porosity, permeability, and thickness) measured in the Neogene sandstone hydrocarbon reservoirs (northern Croatia). The results show that cross-validation itself will not provide appropriate map selection, but, in combination with geometrical features, it can help experts eliminate the solutions with low-probable structures/shapes. The Golden Software licensed program Surfer 15 was used for the interpolations in this study.
The interpolation of small datasets is challenging problem regarding the selection of interpolation methods and type of datasets. Here, for such analysis, the analysed data was taken in two ...hydrocarbon fields (“A” and “B”), located in the western part of the Sava Depression (in Northern Croatia). The selected reservoirs “L” (in the “A” Field) and “K” (“B”) are of Lower Pontian (Upper Miocene) age and belong to the Kloštar-Ivanić Formation. Due to strong tectonics, there are numerous tectonic blocks, each sampled with only a few wells. We selected two variables for interpolation—reservoirs permeabilities and injected volumes of field water. The following interpolation methods are described, compared and applied: Nearest Neighbourhood, Natural Neighbour (for the first time in the Sava Depression) and Inverse Distance Weighting. The last one has been recommended as the most appropriate in this study. Also, the presented research can be repeated in similar clastic environments at the same level hydrocarbon of exploration.
Full text
Available for:
IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
The Holocene, Upper Pleistocene and Middle Pleistocene sediments in the eastern part of the Drava depression the substratum of which is determined by the conditional EK marker Q', are composed in the ...lower part mainly of silts and clays and in the upper part of sands. The thickest parts are about 400m. The composition of the transparent heavy minerals and the result of the paleontological treatment show that the sedimentation was in the lake or swamp with the origin of detritus from the metamorphic rocks and smaller quantity of older clastic sediments.The collected data show the quaternary tectonic activity after the sedimentation of the marker horizon Q'. In the area between the boundary faults of the valley, the faults of the system E.N.E. - W.S.W. (N.E. - S.W.) influenced directly the sedimentation and the folding . They were the consequence of the regional movements and stress strain behaviour of rock masses, which built the structures of the valley.As a result, the horizontal component of the left wing movement is visible along the diagonal system of faults. The vertical movements have also been determined. The greatest amplitudes were along the boundary South fault of the Drava valley, up to 350 m for the period of Middle and Upper Pleistocene, or 90 m for Upper Pleistocene only.
Full text
Available for:
IZUM, KILJ, NUK, ODKLJ, PILJ, PNG, SAZU, UL, UM, UPUK
The authors analyse the process of water re-injection in the hydrocarbon reservoirs/fields in the Upper Miocene sandstone reservoirs, located in the western part of the Sava Depression (Croatia). ...Namely, this is the “A” field with “L” reservoir that currently produces hydrocarbons using a secondary recovery method, i.e., water injection (in fact, re-injection of the field waters). Three regional reservoir variables were analysed: Porosity, permeability and injected water volumes. The quantity of data was small for porosity reservoir “L” and included 25 points; for permeability and injected volumes of water, 10 points each were measured. This study defined selection of mapping algorithms among methods designed for small datasets (fewer than 20 points). Namely, those are inverse distance weighting and nearest and natural neighbourhood. Results were tested using cross-validation and isoline shape recognition, and the inverse distance weighting method is described as the most appropriate approach for mapping permeability and injected volumes in reservoir “L”. Obtained maps made possible the application of the modified geological probability calculation as a tool for prediction of success for future injection (with probability of 0.56). Consequently, it was possible to plan future injection more efficiently, with smaller injected volumes and higher hydrocarbon recovery. Prevention of useless injection, decreasing number of injection wells, saving energy and funds invested in such processes lead to lower environmental impact during the hydrocarbon production.
PDF
