When commercialization of CSEM began, experimental sources were available but no custom source systems existed for large scale, day-to-day operation in ultra- deep water.  There has been a move away from power electronics in pressure canisters towards systems exposed to ambient pressure at 3500 m water depth. Such systems can transmit 1200 A continuous output current, with a typical dipole moment of 360 kAm.  Moreover, the source systems are synchronized to GPS time and have an overall accuracy of ~1%.  EMGS currently has over 10 source systems in operation globally, from tropical to arctic climates.

Surface-towed source

To improve depth of investigation and bandwidth for acquisition in shallow-waters, EMGS developed a high-power, surface-towed source, with deck-mounted power electronics. The system has maximum 7200 A continuous output current with high-frequency components and dipole moment of 2,100 kAm. A horizontal electric dipole antenna is positioned using surface GPS buoys for improved accuracy. The dipole can be towed in 4 knots, and the system is efficient at water depths up to 400m, depending on the geology setting.

Data sheet surface-towed source