A major challenge in well planning and in 3D reservoir modelling is to incorporate seismic information. In a North Sea setting, the wells constitute only a few pinpricks in the reservoir, while the seismic data are acquired in 3D over the whole field. Thus seismic data constitutes the only observations available in the interwell areas.
In this paper we give an introduction to seismic inversion and present three North Sea case studies where inverted seismic data have been used. In the first study inverted seismic data was used to predict the thickness of a specific sand layer in the area around a planned well. In the second study seismic inversion has been used as a means for identifying fairly thick stringers of calcite cementation, In the third study inverted seismic data was used to guide 3D geological modelling.