First CSEM Surveys with a Newly Designed Receiver

A new receiver design for marine CSEM, mainly intended to be used in vertical-vertical CSEM, where both the transmitter and the main receiver component are oriented vertically, was operated in two field surveys for the first time. The design differs strongly from other CSEM receivers and is based on a central vertical pole hinged in a tripod frame. It overcomes previous restrictions in receiver count and operational efficiency in vertical-vertical CSEM. In combination with a vertical 5000A source dipole, 3D data acquisition with 72 receiver positions and 77 pulse positions was performed. Noise levels from acquisition in the Barents Sea and in the Norwegian Sea were close to each other with a slight advantage in the Norwegian Sea. Data from the Barents Sea shows a stronger 12h noise period in the frequency range from 3 to 4Hz. This is in agreement with stronger tidal motions in the Barents Sea. As more receivers are used at the same time the new data sets benefit from additional longer offset data not available in previous data sets. It allows for new ways of processing. Influences from induced polarization for example are offset dependent and can be analyzed in more detail.