Syderiai Underground Gas Storage


In 2009 Lithuania has launched a project on the construction of an underground gas storage facility in order to accumulate the requisite reserve of natural gas and to ensure uninterrupted gas supply to gas consumers. After assessing 129 geological structures located in Lithuania, Syderiai saline aquifer structure located in Telšiai region, occurring at the depth of approx. 1450 m, has been selected as potentially the best candidate.

In order to assess the geological suitability of the structure, in 2009 an appraisal program of the structure was initiated consisting of seismic and geological investigations and reservoir modelling. In 2014 the extensive appraisal program of the structure was completed determining that the structure geologically is suitable for gas storage. After completing a cost and benefit analysis (CBA), it was determined that Syderiai gas storage project should be implemented as a regional project with a working gas capacity of 500 mcm, thus addressing not only Lithuania’s but also Polish gas market needs and guaranteeing the security of supply. In was also determined that in case of necessity the initial 500 mcm of working gas volume of the storage could be further extended.

In consideration of the geological results, further preparatory works of project implementation were initiated in order to secure the financial support from EU funds as well as to ascertain the regional support for the Project. The answer whether the project will be granted financial aid from the EU’s Connecting Europe Facility (CEF) fund will be clear in 2016.

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In case of any technical, economic, political or other type of disruptions of gas supply into Lithuania, the gas reserves stored in Syderiai underground storage facility would allow to guarantee an undisrupted supply of gas to the customers. Reserves stored in the underground gas storage would allow to satisfy gas consumption in Lithuania for up to 52 days.

The new storage facility would also contribute to the development  of both national and regional gas markets, would allow to satisfy seasonal fluctuations in gas consumption, to exploit seasonal fluctuations in gas prices, as well as to optimize the work of Klaipėda LNG terminal. In 2020 after Lithuanian – Polish gas interconnection will be constructed the storage could be used for Polish gas market needs.



Seeking to assess whether the Syderiai geological structure is suitable for construction of a gas storage facility, in 2010-2011 seismic investigations by applying 2D/3D seismic method (Phase I of appraisal program) were conducted in a 150 km2 area in Telšiai region. The results of investigations allowed to determine the composition and characteristics of the geological structure and to project the requirements and scope of further works. Analysis of seismic data has shown that Cambrian layer occurring at the depth of approx. 1450 m contains a large formation suitable for gas storage.

In order to obtain a better understanding of the Syderiai geological structure, is storage potential, to assess the tightness of the faults found in the Eastern and South-Eastern parts as well as to assess other geological parameters of the structure exploratory wells were drilled (Phase II of appraisal program). In 2011-2013 two vertical and two deviated wells were drilled of approx. 1560 m. depth performing detailed investigations in the boreholes.

In 2013-2014 the IIIrd phase of the appraisal program was completed by reinterpreting all the available seismic and geological data from investigations performed in 2010-2013 and creating a reservoir model. This model allowed to assess the reservoir properties and its distribution, to determine sealing properties and integrity of the cap-rock, to calculate the volume of storable gas, injection/production scenarios, approx. investment needs to complete the Project and other vital data.

In order to assess the financial aspects of the Project, a Cost and Benefit (CBA) analysis was completed in 2014 which showed that the most promising project development scenario results in construction of a regional gas storage with a working gas capacity of 500 mcm which implementation would be partially supported by the EU financial aid. Part of the storage capacity would be allocated for the needs of regional partners, primarily for Polish gas market needs, which is represented by high levels of gas consumption (exceeding consumption on Lithuania by 5,5 times), high demand and potential of storage services and upmarket prices for such services.

It is expected the implementation of the Project by commissioning the underground gas storage could be completed till 2021.

Video about opening ceremony of Syderiai investigation works, II Phase.


Preliminary investment of the Syderiai storage project could reach up to EUR 313 million. The preparatory works of the project are co-financed from the State budget and the European Union using the funds of the Trans-European Energy Network (TEN-E) programme (Action No. 2008-G150/08-TREN/08/TEN-E-SI2.528909 and 2011-G192/11-ENER/11/TEN-E-SI2.628721). About 1/3 of all expenses of the Project is being covered by "Lietuvos energijos gamyba“, AB own funds.


Safety is one of the main issues of attention in the operation of underground natural gas storage facilities. A facility can only be constructed in such geological structure which ensures isolation of natural gas deep under the ground. Operators of the facilities must comply with particularly stringent safety and environmental regulations in order to ensure smooth operation of the facilities. Independent ambient air, groundwater and soil analysis provide objective information on the facilities’ impact upon the environment. In the EU the construction and work standards are regulated by the European Standard EN 1918-2:1998 “Gas Supply Systems – Underground Gas Storage – Part1 “.

International Practice

Currently there are approx. 650 underground storage facilities in operation all over the world. The majority of them – approx. 440 – are located in the United States; 153 facilities operate  in the European countries. Lithuania‘s neighboring countries also operate such facilities: Latvia – 1 storage, Poland – 8 storages (one additonal storage is under construction, a few existing ones – under expansion), Belarus – 2 storages and Russian Federation (Kaliningrad region only) – 1 storage.


Project Promoter:
The Ministry of Energy

Implementing body:
"Lietuvos energijos gamyba", AB

Duration of Project implementation:

Funding sources:
The Trans-European Energy Networks (TEN-E) programme, The Republic of Lithuania, "Lietuvos energijos gamyba", AB

Technical indicators: 
Performed investigations and works consists of: 150 km2 of 2D/3D seismic explorations, drilling of two vertical and two deviated wells, seismic ang geological data reinterpretation, creation of static an dynamic reservoir models, completion of cost & benefit analysis (CBA) .

Additional information:
Valentas Neviera, Head of Corporative Communication Division of "Lietuvos energijos gamyba", AB