a) PROJECT NAME: Peak storage facility Grubisno Polje

b) PROJECT DESCRIPTION:

After the completion of the additional tests/data, the project of building the peak storage will be divided in two phases.

I. phase will be the extraction of obtained gas reserves from the gas reservoir/gas field Grubisno polje.

Considering the fact that the underground gas storage is intended to be build in a undepleted gas field, before the construction itself, it is necesary to partially deplete the identified reserves of gas from the gas reservoir.

The remaining, undepleted, portion of gas will be used as a gas cushion for the underground storage. This prior production is planned to last for about one year. In this phase it will be necessary to build facilities and installations for the gas treatment (natural gas plant), supervision system and process managment, connecting pipelines to the wells, connecting pipelines to the main pipeline Virovotica-Kutina, access roads, water system etc. 

First phase of construction with necessary facilities schematically shown on picture 1.



II. phase will be building of the underground gas storage in partially depleted gas reservoir of Grubisno polje.

After the completion of extraction, new peak storage will be build with a working volume of minimal 25 milion m3, with a maximum level of injection capacity up to 1,4 milion m3/per day and maximum level of withdrawal capacity from 1,7 to 2,4 milion m3/per day with a possibility of multiple injection and withdrawal circles during winter season. The primary task of this underground gas storage would be ensuring peak withdrawal capacities during the winter season, or more precisely as a support during withdrawal of gas from the seasonal gas storage in UGS Okoli.

Injection of gas in this storage will be possible when there's „excess„ of gas in the Croatian gas system. It means that peak storage UGS Grubisno Polje will increase total flexibility of Croatian transmission system specially during spring and autumn when there are great fluctuations on demand side to which existing seasonal UGS Okoli cannot respond adequately.

From the facilities in the natural gas plant, that are now facilities of UGS Grubisno polje, it will be necessary to build a compressor station with two compressors powered by electric motors with the capacity of aprx. 700 000 m3/per day (or one compressor with the capacity up to 1 400 000 m3/per day). For the purposes of the gas storage, and according to the available data it will also be necessary to drill and equip new wells.

The number of new necessary wells will be decided afterwards, depending on the determined characteristics of the gas reservoir and the forecasting system model. The realisitc scenario is to build two to maximum four new wells that wolud pass through the gas reservoir in the area of its best hydrodynamic properties and on the basis of the same their trajectorys would be determined (obliquely oriented or horizontal wells).

Second phase of construction with additional facilities (marked red) schematically shown on picture 2.




c) CONTACT DETAILS OF PROJECT PROMOTER:

Podzemno skladiste plina Ltd.
Bruno Ernečić, Director of Development and Investment Sector
e-mail: bruno.ernecic@psp.hr