Třanovice underground gas storage is located in Northern Moravia, 4-14 kilometers to the southwest from Český Těšín. The underground gas storage has been constructed in former gas deposit. The entire deposit consists of four independent units - Nové pole, Západní pole, Čočka, and Staré pole.
Underground gas storage construction preceded by gradual transfer of the stored natural gas between 1982 and 1997. Construction commenced in winter of 1994.
Installation of gas and electrical connections between individual wells and the underground gas storage commenced together with boring of new wells. Well technology with radio data transmission, new access roads, and reconstruction of existing access roads were done later on.
Construction of buildings and operating plants of the underground gas storage area commenced in July, 1999. Buildings and operating plants of Třanovice underground gas storage are located on the area of two hectares.
In 2009 – 2012, with the financial support of the European Union, the storage underwent vast modernization, including the extending of storing capacity to the total of 530 million m3 with a daily production capacity of up to 8 million m3. The increasing of storing capacity was achieved by utilizing previously unused geological structures and by reducing the minimal working pressure in the storage. During the modernization, ten new wells had to be drilled and five old ones renovated, the central area technologies had to be upgraded and four new compressors installed.
Both the newly drilled and renovated wells had to be connected to the central area of the storage, which is why 8.5 km of new pipelines was built and 5.5 of the existing pipelines renovated.
In order to carry out the overall modernization of the central area surface technology, it was necessary, among other alterations, to fit new drying columns, install new transforming plant to increase the input power up to 1 MW, renovate the piping yard, build new microfilters and metering runs and purchase a set of gas air coolers.
From the geological perspective, the deposit is located in a top part of buried valleys on the northern slopes of the elevation so called "Žukovský ridge" of Carboniferous age. Storage horizon is located in lower Badenian basal clastics. From the lithological point of view, the Badenian reservoir rocks consist predominantly of fine- to coarse-grained sandstones and conglomerates. The deposit is located in the mean depth of 445 meters and it is characterized by expansion regime. The caprock is formed by overlaying Badenian claystones and the Silesian and Sub-Silesian units of the outer Carpathian flysch belt.