Abstract: A wireless data communication system for a down hole environment. The system includes a housing containing a sensor, positioned within a tubular, for collecting information and processing the information, a modulator for modulating the information from the sensor into an analog signal, and a sensor antenna electrically connected to the first modulator for generating a modulated electromagnetic wave. The system further includes a probe housing, concentrically disposed within the tubular, comprising a probe antenna for receiving the modulated electromagnetic wave and generating an output, and a demodulator for demodulating the electromagnetic wave received from the sensor to a digital record. A method of wirelessly communicating between a probe and a remote sensor is also disclosed.

Abstract: A device and method for obtaining an electromagnetic propagation measurement of a subterranean geologic formation, with the formation being intersected by a borehole. The device comprises a transmitter for transmitting an electromagnetic signal, and a first and second receiver for receiving the transmitted signal. The device further comprises a circuit for injecting a calibration signal into the first receiver and the second receiver, and a processor for processing the uncalibrated receiver signal and the calibration signal to obtain electromagnetic propagation measurement that is free from errors introduced by the receiving elements of the system. The processor may include a receiver data acquisition circuit for correcting data acquisition errors related to the first receiver and the second receiver.

Abstract: The invention provides a system for determining geologic formation resistivity while drilling and a new method providing compensation for the vertical asymmetries of the tool response and the effects of borehole rugosity. The apparatus and method allows the construction of a tool body considerably shorter in length than previous devices and provides more radial depths of investigation for a given number of transmitter and receiver antennas when compared to previous devices. A method for calibrating data acquisition errors of the system is also described.

Abstract: Well logging apparatus and methods for determining formation resistivity at multiple (>3) depths of investigation. At least one transmitter antenna and at least two receiver antennas are mounted in a logging tool housing, on substantially a common axis. The antennas are untuned coils of wire. Electromagnetic energy is emitted at multiple frequencies from the transmitter into the formation. The receiver antennas, which are spaced apart from each other and from the transmitter, detect reflected electromagnetic energy. Formation resistivity at multiple depths of investigation is determined using only phase differences in the reflected energy at the different frequencies, minimizing false indications of invasion due to mismatch of vertical response with attenuation measurements and also permitting correcting for the effects of varying dielectric constant of the formation.