Abstract: A system for measuring geological data is disclosed. The system includes several transceivers distributed over a geographical area. Each of the transceivers has at least one transmitter and at least one receiver. The transceivers are in communication with each other. The receivers are adapted to measure at least one electrical signal. The transmitters are adapted to inject an electrical current into a subsurface area. The transmitters operate simultaneously to inject the electrical current into the subsurface area simultaneously from a number of locations.

Abstract: A system for measuring geological data is disclosed. The system includes several transceivers distributed over a geographical area. Each of the transceivers has at least one transmitter and at least one receiver. The transceivers are in communication with each other. The receivers are adapted to measure at least one electrical signal. The transmitters are adapted to inject an electrical current into a subsurface area. The transmitters operate simultaneously to inject the electrical current into the subsurface area simultaneously from a number of locations.

Abstract: In electrical resistivity tomography and electrical impedance tomography, interference effects of the metal well casing can be reduced by disposing measurement electrodes in the form of conductive bands around a region of primary insulation on the well casing. Secondary insulation can be provided longitudinally adjacent the primary insulation to further reduce the interference effects. Parameters of the primary and secondary insulation may be determined using finite element methods. The conductive band electrode can connect to a wire of a multi-strand cable using a novel takeout arrangement. Novel measurement methods are also described.