Eszterházy Károly College Faculty of Natural Sciences
The source rock of hydrocarbons are the sedimentary rocks which are rich in organic matter. Between the Palaeozoic and Mesozoic rocks which are constituent rocks of Hungary we can find this kind of species, but most of them are wrinkled during the formation of the Alpine Mountains, cracks developed in them, and become special-status. So the hydrocarbons which were migrated upward from them, released to the atmosphere. The source rocks of domestic petroleum and natural gas are considered to be primarily tertiary and basin sediment formed in reductive environment. In Hungary, the geothermal gradient is higher than the world average this is good for the formation of hydrocarbon. So the rocks can reach the required temperature for the formation of petroleum and natural gas in the one and a half kilometres depth. The hydrocarbons which were migrated from the source rock are accumulated in the reservoir rocks. The Hungarian storage rocks are mainly the Pannonian sandstones, but they are maybe Eocene, Oligocene and Miocene caustic sedimentary rocks, or fractured Mesozoic lime stones and dolomites in which the hydrocarbons arrived with the help of lateral migration from the younger source rock. The Pannonian storage rock usually form hooked vaults over the emphasized Palaeozoic clots. It covers the 20% of domestic necessities of petroleum extraction and 80% of natural gas extraction.
Domestic hydrocarbon zones:
Kisalföld (Mihályi, Répcelak):CO2 gas accumulated in Pannonian sediments.
Zala zone (Budafa, Nagylengyel, Lovászi, etc.): The covered and cracked reservoir rock, Triassic and Cretaceous limestone, dolomite, and Pannonian sandstone. The plants had been largely exhausted
Danube-Tisza Interfluve (Kiskunhalas, Szank,): The reservoir rocks are Miocene conglomerate, sandstone.
Tiszántúl (Pusztaföldvár, Battonya, Algyő, Hajdúszoboszló): The reservoir rocks are Miocene and Pannonian sandstones. In this area the country’s largest petroleum and natural gas plants take place. The most significant domestic hydrocarbon occurrence is in Algyő, here the reservoir rock is the Pannonian sandstone. The largest natural gas plant is in Hajdúszoboszló.
Northern Hungary (Mezőkeresztes, Demjén, Fedémes, Bükkszék): Not significant plants. The reservoir rock is the Oligocene sandstone, the oil has high density, it is hard to mine.