SPREADING OF BRINE DISCHARGED INTO THE PUCK BAY (SOUTH BALTIC SEA): THEORETICAL STUDY VERSUS FIELD OBSERVATIONS

Abstract

Increasing demands for gas storage capacity encouraged Polish Gas and Oil Company (PGNiG) to make use of salt deposits located in the north-eastern part of Poland, in the area bordering on the Gulf of GdaÅ,,sk (South Baltic Sea), and create underground gas stores. A complex of 10 chambers (250x106 m3) was designed to be built at a depth of 800-1600 m. The construction site is located about 4 km away from the sea coast. The drilling of boreholes and diluting of salt rock was proposed as a method of creating the chambers. Owing to ecological reasons, maximum discharge of brine is limited to 300 m3/h with the max. saturation of 250 kg/m3. The Puck Bay is a shallow water body with wind-driven currents and negligible tides. The main difficulty of the investment lay in the effective spreading of brine in the Puck Bay in accordance with all requirements that apply to regions protected by NATURA 2000. The most important restriction was the permitted excess salinity, defined as 0.5 PSU over the natural salinity in the Puck Bay. The location of brine discharge, number and diameters of nozzles, as well as consequences of brine discharge on the Puck Bay water, had been analyzed before the permission to install the system of diffusers was granted by the regional administration. The installation consists of a system of 16 heads spaced every 45 m, each of them equipped with 3 nozzles of 8 mm diameter.