Combined Surface and Cross-hole Electric Tomography for Reservoir Monitoring

In this paper, we introduce an integrated electric/electromagnetic methodology for mapping the dynamic resistivity variations during hydrocarbon production, injection and well intervention. Our approach combines surface and cross-hole measurements and allows obtaining time-lapse models of 3D resistivity distribution between the wells and the surface. The discussion is focused on 3D and 4D inversion of cross-hole DC (Direct Current) measurements, combined with surface-to-borehole DC data. Modelling and inversion of both synthetic and laboratory data confirm that joint cross-hole and surface DC tomography allows mapping reservoir fluid variations even in case of metallic components of the well completion.