Systems, tools and techniques for measuring downhole parameters are provided. The techniques involve providing a downhole tool with a sensing apparatus. The sensing apparatus has at least one source positionable about the downhole tool, at least one sensor electrode positionable about a front face of the downhole tool for measuring electrical signals from the source, and a raised insulating cover positionable along the front face of the downhole tool for defining at least one contact surface. The raised insulating cover extends over at least a portion of the sensor electrode whereby the sensor electrode is positionable adjacent to the subterranean formation for electrically coupling thereto without direct contact therewith.

Systems, tools and techniques for measuring downhole parameters are provided. The techniques involve providing a downhole tool with a sensing apparatus. The sensing apparatus has at least one source positionable about the downhole tool, at least one sensor electrode positionable about a front face of the downhole tool for measuring electrical signals from the source, and a raised insulating cover positionable along the front face of the downhole tool for defining at least one contact surface. The raised insulating cover extends over at least a portion of the sensor electrode whereby the sensor electrode is positionable adjacent to the subterranean formation for electrically coupling thereto without direct contact therewith.

Various embodiments include systems and methods that operate to provide reservoir imaging. The systems and methods can include a number of transmitter antennas and a number of receiving antennas arranged to operate as one or more multi-pole antennas, controlled to generate high resolution cross-well formation images. Additional apparatus, systems, and methods are disclosed.

Various embodiments include systems and methods that operate to provide reservoir imaging. The systems and methods can include a number of transmitter antennas and a number of receiving antennas arranged to operate as one or more multi-pole antennas, controlled to generate high resolution cross-well formation images. Additional apparatus, systems, and methods are disclosed.

Data obtained with an electromagnetic energy transmitter in borehole to surface electromagnetic (BSEM) transmitter is processed. The processed data provides measures of detected electromagnetic fields, induced polarization and electromagnetic well logging information of interest for surveying and mapping of subsurface formations.

Data obtained with an electromagnetic energy transmitter in borehole to surface electromagnetic (BSEM) transmitter is processed. The processed data provides measures of detected electromagnetic fields, induced polarization and electromagnetic well logging information of interest for surveying and mapping of subsurface formations.

Some examples of transferring data from a subsurface of a wellbore using well fluids include positioning multiple data recording devices at a subsurface location in a wellbore. When a well fluid flows through the wellbore past the subsurface location to a surface, each data recording device is configured to receive and store data describing subsurface wellbore conditions at or near the subsurface location. At least a portion of the data describing the subsurface wellbore conditions are stored on each data recording device. Each data recording device is released from the subsurface location. The well fluid flows each data recording device to the surface.

Some examples of transferring data from a subsurface of a wellbore using well fluids include positioning multiple data recording devices at a subsurface location in a wellbore. When a well fluid flows through the wellbore past the subsurface location to a surface, each data recording device is configured to receive and store data describing subsurface wellbore conditions at or near the subsurface location. At least a portion of the data describing the subsurface wellbore conditions are stored on each data recording device. Each data recording device is released from the subsurface location. The well fluid flows each data recording device to the surface.

A method for a multichannel geophysical data acquisition system is provided in the field of electrical resistivity tomography. Individual and autonomous node operating systems are provided. Separate communication channels for upstream and downstream data transfer, high voltage transfer and synchronization signals are provided. A novel use of high voltage isolation barriers is also provided. A direct memory access data transfer process is provided.

A method for a multichannel geophysical data acquisition system is provided in the field of electrical resistivity tomography. Individual and autonomous node operating systems are provided. Separate communication channels for upstream and downstream data transfer, high voltage transfer and synchronization signals are provided. A novel use of high voltage isolation barriers is also provided. A direct memory access data transfer process is provided.