Monitoring 3D reservoirs from CSEM data using a level set technique

A new shape reconstruction technique is presented for Controlled Source ElectroMagnetic (CSEM) imaging of subsurface structures such as reservoirs. The technique can in principle be used both for exploration and for monitoring of active reservoirs. The main characteristic of our algorithm is to incorporate certain types of a priori information into the estimation which has the potential to increase resolution. In particular, we assume that only the shape and topology of the structures need to be determined from the data. The background is assumed to be known from alternative tools such as seismics, well-logs or geological information. The full system of Maxwell's equations in 3D is employed for the inversion and combined with a level set technique for representing shapes. Numerical examples are presented which show that very good reconstructions can be obtained with this novel reconstruction technique from CSEM data for realistic simulated situations.