1. Statoil Research Centre, Trondheim, Norway and The Norwegian University of Science and Technology, Department of Geoscience and Petroleum, Trondheim, Norway..
2. Statoil Research Centre, Trondheim, Norway..
3. ETH Zurich, Institute of Geophysics, Zurich, Switzerland..
4. The Norwegian University of Science and Technology, Department of Geoscience and Petroleum, Trondheim, Norway..