Electromagnetic sensor cable and electrical configuration therefor

An electromagnetic sensor cable, comprising cable components:

• sensor cable segments directly connected at lateral ends to one another, each sensor cable segment comprising:
• spaced apart electrodes on the sensor cable segment;
• through wires extending from one longitudinal end to the other longitudinal end of the sensor cable segment without connection to an electrode, and
• electrical conductors in the sensor cable segment coupled to the electrodes such that at least one of the electrodes is electrically connectible at at least one longitudinal end of the sensor cable segment,
• wherein the number of the cable components are related to each other by the relationship:
• W=(Q/2+M)=(Q/2+Q·(N−1)/2);
• wherein N is the number of the sensor cable segments,
• wherein Q is the number of the spaced apart electrodes,
• wherein M is the number of the through wires, and
• wherein W-M is the number of the electrical conductors.

An electromagnetic survey system comprising:

• a survey vessel;
• a tow cable connected at a first end to the survey vessel;
• an electromagnetic sensor cable comprising cable components:
• a first sensor cable segment comprising:
• a plurality of spaced apart electrodes on the first sensor cable segment;
• and
• electrical conductors in the first sensor cable segment coupled to the electrodes such that at least one of the electrodes is electrically connectable at at least one longitudinal end of the first sensor cable segment,
• a second sensor cable segment comprising:
• a plurality of spaced apart electrodes on the second sensor cable segment;
• and
• electrical conductors in the second sensor cable segment coupled to the electrodes such that at least one of the electrodes is electrically connectible at at least one longitudinal end of the second sensor cable segment, and
• a first signal processing and configuration module having signal processing circuitry configured to perform at least one of:
• measuring voltages across selected pairs of electrodes, and communicating signals representative of voltages across selected pairs of electrodes,
• wherein the cable components are each configured to connect at the lateral ends one to another, and to a second end of the tow cable.

An method of conducting an electromagnetic survey comprising:

• towing an electromagnetic sensor cable through a body of water with a survey vessel, wherein a tow cable is connected at a first end to the survey vessel, and the electromagnetic sensor cable comprises cable components:
• a first sensor cable segment comprising:
• a plurality of spaced apart electrodes on the first sensor cable segment, and
• electrical conductors in the first sensor cable segment coupled to the electrodes such that at least one of the electrodes is electrically connectible at at least one longitudinal end of the first sensor cable segment,
• a second sensor cable segment comprising:
• a plurality of spaced apart electrodes on the second sensor cable segment, and
• electrical conductors in the second sensor cable segment coupled to the electrodes such that at least one of the electrodes is electrically connectible at at least one longitudinal end of the second sensor cable segment, and
• a first signal processing and configuration module having signal processing circuitry configured to perform at least one of measuring voltages across selected pairs of electrodes, and communicating signals representative of voltages across selected pairs of electrodes,
• wherein the cable components are each configured to connect at the lateral ends one to another, and to a second end of the tow cable.