Efficient field management and appraisal rely on a good understanding of reservoir geology and recovery efficiency. This requires co-operation and good communication between different disciplines. This paper presents and demonstrates the shared earth model approach, to encourage integration and co-operation between disciplines producing more reliable reservoir characterisation and performance prediction. A North Sea field is used as an example to illustrate the development and use of the shared earth model. The way in which it brings together the subsurface disciplines is shown by dynamic data feedback and seismic validation of simulator predictions.