Oil and gas deposits in the Czech Republic 4/09

The small oil and gas deposits in the Czech Republic are located mainly in south Moravia. Their exploration started in the early years of 20th century, fi rst commercial oil extraction opened in 1919. In 2005 340,600 m³ of crude oil and 98.75 million m³ of natural gas was extracted.

Oil deposits of the Czech Republic are confi ned to the Vienna - Moravia oil and gas-bearing province. The deposits are distributed over a great number of individual oil-bearing structures and producing horizons situated at the depth going down to 2,800 m. The most productive oil-bearing rocks are represented by sandstones of the Middle and/or the Upper Badenian. The largest deposit of this area (Hrušky) whose major part has already been extracted, serves as an underground gas storage.

Another region in which oil is anticipated to occur lies in the Moravian part of the Carpathian foredeep where oil exploration still continues. The most important accumulations occur particularly in the weathered crystalline and Paleozoic rocks. Light, sulphur free, paraffi n to paraffi n - naphthenic oil prevail in this fi eld. Uhřice and Kloboučky (in the Ždánice region) are the only oil deposits in this area.

Three grades of oil were extracted in 1999 with specifi c gravity from 856 to 930 kg/m3 at 20°C, 20-33° API and with content of sulphur 0.080.32 % by weight.

Natural gas deposits are in reservoirs that contain oil. The deposits are mostly located in south Moravian part of the Vienna Basin. Northern part of the basin contains rather oil deposits. Extracted natural gas contains from 87.2 to 98.8 % of CH4, its caloric value is 35.6-37.7 MJ/m3 (dry natural gas at 0°C), specifi c gravity is 0.72-0.85 kg/m3 (at 0°C) and content H2S is under l mg/m3. The Carpathian foredeep is considered as a promising area for the occurrence of natural gas. The composition of local gas deposits varies considerably. The Dolní Dunajovice deposit is characteristic of high content of methane (98 %) whereas the deposit Kostelanywest contains only 70 % methane and is high in helium and argon which can be extracted on industrial scale.

In Silesia, specifi cally between Příbor and Český Těšín, the gas deposits are mostly confi ned to the weathered and tectonically affected Carboniferous paleorelief. The origin of these gas deposits being developed close to the top of the Carboniferous morphological elevations has not been deciphered yet. Ideas about the gas to have originated during coalifi cation of the local coal seams has little support and its origin is considered to be connected with the neoid movements which led to the origin of natural hydrocarbons. This applies particularly to the gas deposits of Žukov, Bruzovice and Příbor. Part of the Příbor gas deposit is used as an underground gas storage.

Natural gas of obviously Carboniferous origin and age is extracted during so-called degasifi cation of coal seams of the Czech part of the Upper Silesian coal basin. Its quality varies considerably depending on the method of extraction and technical limitations related to degasifi cation.

History

The first experimental oil-well was opened on March 27, 1900 near Moravian village Bohuslavice (today part of Kyjov), the second opened in the same year. Since the extraction would be too costly the area was abandoned until 1917. In 1919 the company Moravská těžařská společnost opened the fi rst commercial well. In 1925 the company owned 25 wells in the area. During World War II the industry became strategically important for German war effort - the largest company, DEA (Deutsche Erdöl A.G.), had 1,200 wells just around Hodonín.

On January 1, 1946 all existing oil drilling companies were merged into single organisation, Československé naftové závody (ČNZ). In 1958 the company merged with similar organisation from Slovakia and named Moravské naftové doly. In 1990 the Slovakian part became independent.

Currently, the company Moravské naftové doly, a.s. operates the wells, underground gas storage facilities and crude oil processing plants. Local production covers only very small fraction of demand in the Czech Republic. E.g. in 1999 176 kilotons of crude oil was extracted locally and 5,997 kilotons was imported.

Jarmila Bednaříková

Arnošt Thon: Naftový průmysl na území Československa (Oil industry in Czechoslovakia), 1984

Vocabulary:
deposit                                           uložení, nános, usazenina
crude                                             surový
confine                                           omezit, ohraničit
oil-bearing                                      roponosný, naftonosný
horizon                                           patro
anticipate                                        odhadovat
weathered                                       zvětralý
prevail                                            převládat
deciphere                                       rozluštit
degasifi cation                                 odvětrání plynů
seam                                             spára, rozsedlina

Comprehension:
Which town is used as an underground gas storage?
When was the fi rst experimental oil-well opened?
What is Dolní Dunajovice deposit characteristic of?
Where are oil and gas deposits in the Czech republic located mainly?