| Abstract |
Geothermal research and development in Bosnia and Herzegovina in a period 2005 -2009 has been somehow at a higher level than before. Geotectonic zones in Bosnia and Herzegovina are the following: 1) Sava-Vardar Zone (Active continental margin); 2) The Dinaride Ophiolite Zone; 3) The Bosnian Flysch Zone (Passive continental margin); 4) Allochtonous Paleozoic and Triassic formations from Mid-Bosnian Schist Mountains, Una – Sana Nappe, Durmitor Nappe and 5) Dinaric carbonate platform. A greater number of geothermal energy deposits of low enthalpy are encountered in Bosnia and Herzegovina in all geotectonic zones except zone 5). According to boreholes data conductive geothermal gradients vary from G=28,2 - 49,6°C/km and heat flow values q = 60 – 88,7 mW/m2 and maximal convective values G=66,6°C/km and q=134,9 mW/m2 in Active continental margin, more less values are in Dinaric Ophiolite Zone, Passive continental margin and Mid-Bosnian Schist Mountains. The temperatures measured in Active continental margin vary from 39-62°C at 1000 m, 78 – 101°C at 2000 m, 111 – 147°C at 3000 m and 176 – 209 °C at 5000 m below surface. Significantly lower values of gradients and heat flows are in Dinaric carbonate platform 10-20°C/km and 20-50 mW/m2. The extreme lower temperature values (25-38°C at 1000 m) are supposed in Dinaric carbonate platform on the basis of only one drill hole in Bosnia and Herzegovina and ten drill holes in adjacent areas of Croatia and Montenegro. The largest positive geothermal anomalies are in the Pannonian Basin (Active continental margin); minor potential is in area of Allochtonous Paleozoic and Triassic formations and practically without geothermal potentials in Outer Dinarides (Dinaric carbonate platform). The main geothermal lower reservoirs in Pannonian Basin are situated in Middle and Upper Triassic and upper reservoirs of minor enthalpy are in Cretaceous and Tertiary marine sediments. Triassic aquifers occur deeper of 1500 m below surface of terrain. Thickness of Triassic reservoirs is supposed 500-800 m and its area is 6500 km2. Numerous separate reservoirs of minor geothermal potentials are in Dinaric Ophiolite Zone, The Bosnian Flysch Zone, Allochtonous Paleozoic and Triassic formations from Mid-Bosnian Schist Mountains with main reservoirs in Triassic carbonate rocks. Direct use of geothermal energy is mainly attributed to bathing and swimming (including balneology), space heating, less for geothermal heat pumps, greenhouses and industrial use. There are 22 thermal spas and recreations centers where swimming pools are heated by geothermal water directly or indirectly through heat exchangers and GHPs. Thermal spas and recreations centers are predominant thermal localities for direct heat use. At four thermal spas geothermal heat pumps are included. Total available powers on 90 deposits of thermal and thermomineral waters are ca 250 MWt (referent to 10°C) whereas the utilization included in 31 deposits only with total power ca 200 MWt with same temperature reference. As the temperature outputs are far higher than 10 °C, the real power utilization is much lower. During the last 5 years exploration and development have resulted in only 5 new wells whit a total depth of about 1,2 km. One of them encountered water temperatures of 44°C in Triassic carbonate rocks in Dinaric Ophiolite Zone. It is planned exploration and use of hydrogeothermal potentials in area of town Bijeljina (Pannonian Basin) which includes drilling 5 wells of single depth of 2500 m for district heating. |