Cableless seismic sensors and methods for recharging

Ground equipment for use in a seismic data acquisition system, the ground equipment comprising:

• a surface unit that is placed on a ground surface, the surface unit comprising:
• a first wireless communication module;
• and
• a power supply mechanism transmitter coil;
• and
• a wireless field digitizer unit that is placed underground less than 1 m under the surface unit, the wireless field digitizer unit comprising:
• a second wireless communication module in communication with the first wireless communication module to exchange digital data between the first and second wireless communication modules;
• and
• a power supply mechanism receiver coil, the power supply mechanism receiver coil magnetically coupled to the power supply mechanism transmitter coil to transmit electrical energy wirelessly from the surface unit to the wireless field digitizer;
• wherein the wireless field digitizer unit is separate from and physically disconnected from the surface unit.

A seismic data acquisition system comprising:

• a recording unit to record acquired seismic data;
• ground equipment comprising:
• a plurality of surface units, each surface unit being placed on ground surface, in communication with the recording unit and comprising:
• a first wireless communication module;
• and
• a power supply mechanism transmitter coil;
• and
• a plurality of wireless field digitizer units, each wireless field digitizing unit being placed underground at less than 1 m from one of the surface units, each of the wireless field digitizer units comprising:
• a seismic sensor unit;
• a second wireless communication module in communication with the seismic sensor unit and one of the first wireless communication modules to exchange digital data between the first and second wireless communication modules;
• and
• a power supply mechanism receiver coil, the power supply mechanism receiver coil magnetically coupled to the power supply mechanism transmitter coil in at least one of the surface units to transmit electrical energy wirelessly from the surface unit to the wireless field digitizer.