Open Conference Systems, Doyen Velimir Kranjec

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Academician Velimir Kranjec (17 June 1930 – 7 February 2002) – doyen of the Croatian geology
Josipa Velić, Tomislav Malvić

Last modified: 2017-06-18


Extended abstract

In Fabruary 2017, the 15 years passed from the death of Acad. Velimir Kranjec. He was long-time university professor, distinguished scientist and mentor, who is his lifetime spent at Faculty of Mining, Geology and Petroleum Engineering in (present day) Department for Geology and Geological Engineering. He established more collegiums, wrote dozens scientific papers, mentored doctoral, master and graduated thesis and directly influenced in all aspects of geological, geophysical and geochemical interpretations. Especially it was reflected in domain of exploration and production of hydrocarbons, what correlated with the most successful period of the Croatian petroleum industry (70’s to 90’s of the 20th century).

Acad. Velimir Kranjec was born 17th June 1930, in Gornji Šarampov, in vicinity of Ivanić-Grad, as child of Andrija and Milka (b. Pečić). He died 7th February 2002 in Zagreb. With his wife, Vesna, he raised two children, daughter Željka, prof. piano, and son Zoran, grad. in Geology.

He graduated at Faculty of Technics at University of Zagreb in the 1955, obtaining the title of Graduate Engineer of Mining Geology. Doctoral thesis had been defended in the 1965, at the Faculty of Mining, Geology and Petroleum Engineering (University of Zagreb). After graduation, he started as Assistant in the Department for Petroleum and Coal Geology (Faculty of Technics). Assistant Professor was in the 1965, in the Dept. for General and Applied Geology at the Faculty of Mining, Geology and Petroleum Engineering, Associate Professor in the 1969, and Full Professor in the 1973 in the Dept. for Engineering Geology, Hydrogeology and Geology of Oil and Coal. It is valuable to recognise the changing of department title: from definition of Geology of Fossil Fuels, then General Geology (it was first time that general component followed new, young employers knowledge), followed by Applied Geology (as Engineering Geology and Hydrogeology started to develop). As results the name extended in long form as “Department for Engineering Geology, Hydrogeology and Geology of Oil and Coal”, eventually finished in present-day “Department for Geology and Geological Engineering”.

Regarding his membership in the Croatian Academy of Science and Arts the following facts are valid: associate member in 1975 (only 45 years old), extraordinary member in 1986 and full member in 1991, all in Department of Natural Sciences. Acad. Kranjec held numerous positions. He was president of the Scientific Council for Oil in Academy (1985-1989), president of the Croatian Geological Society (1972-1974), member of INQUA (The International Union for Quaternary Science) – Neotectonic Commision in Stockholm and others.

He received several awards and recognitions. It was «Ruđer Bošković» award (1983) for significant scientific and researching work in Natural Sciences, especially in Geology of Oil; plaque of honorary and deserving members of the Academy’s Scientific Council for Petroleum, honorary and deserving member of the Society of Engineers and Technicians of Croatia, and in the 1998 the Medal of the University of Zagreb for science, lecturing, and contribution to the University. He taught the numerous subjects for students of all faculty’s profiles (mining, geology and petroleum engineering) as follows:

-          Geological mapping,

-          Structural geology,

-          Subsurface mapping,

-          Geology of oil and gas reservoirs,

-          Geology of fluid reservoirs.

He was co-lecturer also at postgraduate study in the subjects:

-          Selected topics from tectonics and structural geology (with Acad. M. Herak and Prof. E. Prelogović),

-          Neotectonics and morphometry (with Prof. E. Prelogović).

Acad. Kranjec was mentor in 65 graduate, 10 master and 12 doctoral thesis. In his time, 12 doctoral students was enormous large number and is clearly correlated with the largest success of the Croatian petroleum industry.

His bibliography is given in the Memorial dedicated to died academicians (issue 111), collected by Prof. Z. Hernitz and Prof. B. Saftić. It included 83 papers, mostly in Croatian journals (Nafta, Geološki vjesnik, Pomorski zbornik and different proceedings). Sixty of them had been analysed in purpose to defined topics of the largest activity of Acad. Kranjec. Those are:

-  geology and subsurface geology,

-  tectonics,

-  hydrogeology and

-  geology of oil and gas (geology of caustobiolith).

Acad. Kranjec very special emphasised possibility of forming structural and stratigraphic traps in, mostly well explored, areas of the Pannonian Basin System, taking into consideration also the youngest neotectonics. In one of the last papers he pointed out that, with reasons, new discoveries can be expected at very large depths for gas-condensate, and the shallow for pure gas reservoirs.

Furthermore, in several papers he described hydrocarbon settings in the Adriatic, e.g., hydrocarbon potential of carbonates and evaporites. The proposals for further explorations, especially gas, in the vicinity of discovered gas reservoirs had been given. Also, he evaluated the Dinarides as area with potential hydrocarbon reserves.

Here are selected two, very valuable, works for some more detailed analysis. The first came from the very beginning of his work. The second is form the top of his scientific efforts about petroleum geology settings in the Croatia. That is dissertation, printed in Tuzla (Bosnia and Herzegovina) 1969 in the Institute for Mining and Chemo-Technological Exploration, and paper from 1990 about the Sava and Drava area as well as the Adriatic subsurface.

Acad. Kranjec, in his dissertation, encompassed the wider Tuzla area, presenting detail geological map with practical meaning. There are deposit of lignite, brown and hard coal, salt, oil, asbestos and quartzite sand. In the lignite mine “Kreka” geologists of “Geoistraživanja” Inc. and Prof. Franjo Ožegović made a large scaled geological mapping and hydrogeology and mining geology explorations. Later, Acad. Kranjec entered in the team, made his own explorations, and prepared detail geological map 1:25000. The first results had been announced in two papers in the 1960. One of the dissertation achievement is synthesis of different data: palaeontological (especially micropalaeontological), previously obtained by palaeontologist V. Amšel and Acad. V. Kochansky-Devide (her birth anniversary was held in the 2015). The numerous palaeontological samples had been collected and determined large number of new species of valenciennes and congeria fossils, Tortonian and Sarmatian microfauna, coal bed flora, Eocene fauna and Upper Cretaceous microfauna (Figure 1). Moreover, there were scoped details in settings and composition that pointed out possible correlation with the Vienna Basin (Figure 2). It was crucial for set basics of further petroleum geology explorations.

Figure 1: Selected page with text from Acad. Kranjec dissertation with list of fossil fauna 

Here is neccessary to give some basic information about Prof. Franjo Ožegović (19th July 1903 – 1 July 1978), who established Geology of Oil and Coal in Croatia (Dečak, 2009). How? In July 1940, he was employed as assistant in the Mining Department of viceroy goverment in the Banovina of Croatia, working on the mapping of the Gojlo wider area and locating the first wells drilled in the WWII. In September 1948 the company for oil exploration was established in Zagreb. Acad. Kranjec located the first exploration well “Kr-1”, which discovered the first (after war) oil filed in Croatia. It was the Križ-Šumećani Field. In the period 1945-1949, he was honorary lecturer at the faculty of Technics from the subject Geology of Coal and Oil. He was quickly promoted in Assistant, Associate and Full Professor, also being chairman of the Department for geology of oil and Coal, i.e. Department for General and Applied Geology. He was two times vice-dean and dean (1959-1960) on the Faculty of Technology. Prof. Ožegović was the president of the Croatian Geological Society, editor of the “Nafta” journal, first honorary member of the (Academy) Scientific Council for Oil and the Croatian Geological Society. He wrote numerous scientific and professional papers, mostly about stratigraphic settings of oil reservoirs in the Croatian part of the Pannonian Basin System.

Figure 2: Comparison of the Congeria beds facies in the Tuzla and Vienna Basins (Kranjec, 1969) 

In his works, Acad. Kranjec often considered divisions or selections of the Croatian reservoirs in the Pannonian Basin System. It was possible only after perennial and systematic geological, geophysical and geochemical researching, what resulted in synthesis published in the 1972 (Kranjec, 1972). There was suggested selection of reservoirs in three groups, regarding tectonic settings and location in the Sava and Drava Depressions. Those are:

- buried hills, mostly shallow and on the depression’s margins (Šumečani, Bunjani, Kloštar, Đeletovci, Ilača, Privlaka),

- faulted anticlines with three sub-groups: (I) anticlines along marginal depressional faults (Dugo selo, Lipovljani, Jagnjedovac); (II) anticlines located deeper and oriented parallel with depressions; (III) the deepest structures (Stružec, Beničanci),

- structures formed as results on magmatic intrusions, as domes or panels (Cabuna, Bizovac, Crnac and others).

At 30 pages (Kranjec, 1990), he continued that topic based on (then) recent subsurface geological explorations. His attention was directed to heritable and differential structures, which are not vertically similarly reflected, i.e., there are more or less different forms at different structural levels (borders or markers). Such different structural shapes are possible thanks to influences developed during uplifting or downlifting in geological history, especially neotectonic phase. The Ježevo structure was specially studied and represented as example of vertically different forms and shapes. The factors for such structural results could be:

- different rates of Neogene and Quaternary block sinking,

- tectonical and erosional unconformities in the younger Neogene-Quaternary and older sediments (in the Adriatic offshore),

- intrusions (older Mesozoic intrusions) and

- salt diapirism (of different rates in the Adriatic offshore).

All mentions and examples obtained the huge importance for further exploration and practice. It is why differential structures, especially in deeper parts of Croatian depression in the Pannonian Basin, where a low number of wells reached pre-Neogene basement, probably represents extensions of known prospects. In other words, it could be locations for “new closer or distanced reservoir or satellite fields, i.e. separate cartographic projections” – cited according to Kranjec, 1990 (Figure 3, Figure 4, Figure 5, Figure 6).

Figure 3: Correlation section across the Ježevo Field and adjacent area wells in the Sava Depression. The thick lines mark opposite structural shapes (Kranjec, 1990)

For Croatian petroleum geology, there are several very valuable synthetic works (Filjak et al., 1969; Kranjec and Vugrinec, 1978; Kranjec, 1982; Kranjec and Vugrinec, 1982; Kranjec et al., 1987). Acad. Kranjec showed as excellent connoisseur of the course and results in the complete subsurface geological explorations in all parts of Croatia, so he was able gave recommendations. Those texts are important even today, specially for young researchers that just come in very interesting and exciting, detective world of oil, gas and geothermal reservoirs exploration.

Figure 4: Heritage structures in the Croatian Adriatic offshore (Kranjec, 1990)

Figure 5: Seismic sections of the Jabuka Island diapir in the Adriatic Sea (Kranjec, 1990)

Figure 6: Seismic section shows tectonical-erosional unconformity between Plio-Quaternary and older sediments (Kranjec, 1990)


Dečak, I. (2009): Franjo Ožegović – prvi hrvatski naftni geolog (Franjo Ožegović – the first Croatian petroleum geologist). Cris, XI., 1/2009, 251-256.

HAZU (2003): Velimir Kranjec 1930.-2002. (Velimir Kranjec 1930-2002). Zagreb, 1-30.

Filjak, R., Kranjec, V., Nowinski, A. (1969.): Razvoj i aktualni zadaci u primjeni geologije, geofizike i geokemije pri istraživanju nafte i plina u Jugoslaviji (Development and actual tasks in application of geology, geophysics and geochemistry in oil and gas exploration in Yugoslavia). Nafta, Zagreb, 20/8, 389-394.

Kranjec, V. (1969): Geološka građa šireg Tuzlanskog područja (Geological settings of the wider Tuzla area). Dissertation. Institut za rudarska i hemijsko-tehnološka istraživanja. Tuzla, 282 +2. p.

Kranjec, V. (1972): Subsurface  structures in the Sava and Drava river depresions and their classification. Bull. sci. Cons. Akad. Yougosl., Zagreb, (A), 17/11-12, 362-363.

Kranjec, V (1982.): Tendencije i neki problemi najnovijih istraživanja nafte i plina u glavnim područjima Jugoslavije (Tendencies and some problems in the newest explorations of oil and gas in the main Yugoslav areas). Nafta, Zagreb, 33/9, 479-482.

Kranjec, V. (1990): Neke promjene ocrta dubinskogeoloških struktura i njihovo naftnogeološko značenje u savsko-dravskom području i podmorju Jadrana (Some changes in deep geological structures forms and their oil-geological meaning in the Sava and Drava areas and the Adriatic offshore). Rad Jugosl. Akad. Znan. umjetn., Zagreb, 449 /Razr. prir. znan., 24, 195-225.

Kranjec, V & Vugirnec, J. (1978.): Razvoj geologije nafte u SR Hrvatskoj od 1951.1976. godine. Geol. vjesnih, Zagreb, 30/2, 665-676.

Kranjec, V. & Vugrinec , J. (1982.): Razvoj geologije nafte u SR Hrvatskoj od 1976. do 1981. god. (Development of petroleum geology in period 1976-1981 in the Croatia). Geol. vjesnik, Zagreb, 35, 247-253.

Kranjec, V., Aljinović, B., Šparica, M., Krulc, Z. (1987.): On some new results and problems of geological and geophysical exploration for oil and gas in the Sava-Drava river area, the Outer Dinarides and in the Adriatic. Nafta, Zagreb.38/4-5, 189-204.

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geology, history, Croatian, Velimir Kranjec

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