Oil Extraction and Groundwater Monitoring2014-04-04
Monitoring data show that oil extraction in Lithuania does not have a major impact on the environment: dangerous for the environment petroleum products are not present in the groundwater.
Oil has been extracted in Lithuania since 1990. Permits to use hydrocarbon resources (to carry out search / exploration) in Lithuania has been issued to six companies: Lotos-Geonafta AB, Minijos Nafta UAB, Manifoldas UAB, Genčių Nafta UAB, LL Investicijos UAB, TanOil UAB. At the beginning of 2014, oil was being extracted from 15 oil deposits.
From 1990 until the end of 2013, Lithuania extracted ~ 4.3 million tons (5.4 million cubic meters) of oil. The forecasted balance of traditional exploitable oil resources is 2.2 million tons.
In Lithuania, 86,110 tones (104,970 cubic meters) of oil were extracted in 2013. With the depletion of oil extraction, the amount of the pumped to the surface large-mineralization groundwater is rising (brine resulting from the separation of oil from water). According to the Protection of Groundwater Against Pollution Rules, brine can be returned to the same aquifers from which oil is extracted. This is usually sodium chloride water. In 2013, more than 1 million cubic meters of brine was pumped into the injection boreholes.
The groundwater monitoring of oil production is currently governed by the environmental monitoring regulations for economic operators. According to them, an eco-geological survey has to be carried out in each mining area and a groundwater monitoring program has to be prepared. Currently, shallow groundwater monitoring is carried out in 19 oil extraction facilities, which are equipped with more than 100 monitoring wells. During the observation period, more than 2,000 chemical analyzes of water have been accumulated.
Data from the many years of monitoring show that the oil-extraction sites do not have a major impact on the environment: environmentally hazardous petroleum products have not been detected in groundwater. A large part of the available information indicates that ground water at the extraction sites remains at the background level (36 percent) or is in good condition (52 percent).
In the monitoring wells that are set up near injection wells the limit values exceeding the chloride content in the groundwater can be observed. The observed increase is 12 percent. This indicates that when injecting brine into the deep layers, the technological procedures are violated and a certain amount of salt gets into the environment. However, this effect occurs in the local area and does not spread beyond the limits of the extraction sites.
Public Information Division