Controlled Source Electro Magnetics (CSEM) is promising exploration technology, in that it has the ability to distinguish resistive hydrocarbon reservoirs from conductive wet sands in the subsurface. CSEM data is particularly powerful when combined with seismic and well data. Using seismic and well log data to aid in constraining an inversion of CSEM data may significantly improve the results of the inversion. This paper describes a new model for linking electro-magnetic properties (resistivity) and acoustic properties (p-wave velocity).