Provide are compositions and methods for electromagnetic (EM) surveying of subsurface hydrocarbon reservoirs using a giant dielectric material as a contrast agent. An injection fluid composition for EM surveying may include an aqueous fluid and giant dielectric nanoparticles having a dielectric constant of at least 10000 in the 1 Hz to 1 MHz frequency range. EM surveying of a subsurface hydrocarbon reservoirs may be performed by introducing an injection fluid having the giant dielectric nanoparticles into the subsurface hydrocarbon reservoir and generating an image of the position of the injection fluid from a transit time of emitted EM energy that traveled through the reservoir.