1. Institute of Geology and Geochemistry of Petroleum and Coal, Energy and Mineral Resources Group, RWTH-Aachen Univ., Germany.
2. Institute of Geology and Geochemistry of Petroleum and Coal, Energy and Mineral Resources Group, RWTH-Aachen Univ., Germany; Applied Geophysics and Geothermal Energy, E.ON Energy Research Center, RWTH-Aachen Univ., Germany.
3. Applied Geophysics and Geothermal Energy, E.ON Energy Research Center, RWTH-Aachen Univ., Germany.