The PetroMarker transmitter systems produces an output of up to 6,000 A, to ensure large depth penetration and a sufficiently strong subsurface response at the receivers.
The transmitter system consists of three main components; a pulse generator, two electrodes constituting the dipole antenna, and an a-frame for launch and recovery of the electrodes.
The dipole antenna consists of two steel electrodes, where one electrode is suspended a given distance below the survey vessel, and the other electrode sits on the seabed. Both electrodes are designed to have large surface areas, to efficiently push strong DC currents into the sea water. The return current goes from the lower to the upper electrode through the sea water, and the electric field associated with this flow of current induces a primary field which propagates into the subsurface.
The pulse generator is basically a DC current generator which is capable of creating square bipolar pulses with sharp ramp-ups and cutoffs. It is the rapid cutoff from maximum output current to zero current which induces the secondary field that propagates from the subsurface back to the receivers.
The a-frame is designed to ease launch and recovery of the dipole electrodes.
On a regular basis, two such transmitter systems, each capable of an output of up to 3,000 A, are employed simultaneously.
The electric modules and the controlling electronics are housed in air-conditioned, water-cooled containers which can be shipped around at will.