Shallow marine electromagnetic hydrocarbon prospecting

A method for determining electrical properties of a submarine petroleum fluid-bearing formation under overburden geological layers of thickness (s) under a seafloor of a sea. The method includes:*arranging one or more transmitter antennas in the sea, and arranging one or more electromagnetic receivers in the sea, *the sea having a shallow sea depth (d) of 50-350 meters; *using the transmitter antenna transmitting electromagnetic signals of one or more pulses having frequency of very low frequency between 0.01 Hz and 0.10 Hz; *using the receiver antennas having an offset from the transmitter, for receiving propagated electro-magnetic signals due to the emitted electromagnetic signals; *analyzing one or more components of the received signals from receivers having offsets between about 1 km and 12 km, whether the signals differ significantly from a corresponding signal that would occur from a water-bearing formation, indicating a petroleum fluid-bearing formation.