Abstract: A method for inverting dielectric logging tool measurement data to estimate an electrical characteristic of an earth formation includes: receiving measurement data from the logging tool having a transmitter antenna and receiver antennas spaced known distances from the transmitter antenna; establishing an equation relating magnetic field measurements made by the receiver antennas to the distances and a wave vector; establishing an error equation that quantifies a difference between the magnetic field measurements made by the receiver antennas to magnetic field measurements made by the receiver antennas that would be obtained with an estimated formation electrical characteristic; calculating an error using the error equation for an initial estimated value of the wave vector that comprises a term having a first number multiplied times a second number of radians to provide a plurality of calculated errors; and determining a minimum error from the plurality of calculated errors to estimate the electrical character

Abstract: A method for inverting dielectric logging tool measurement data to estimate an electrical characteristic of an earth formation includes: receiving measurement data from the logging tool having a transmitter antenna and receiver antennas spaced known distances from the transmitter antenna; establishing an equation relating magnetic field measurements made by the receiver antennas to the distances and a wave vector; establishing an error equation that quantifies a difference between the magnetic field measurements made by the receiver antennas to magnetic field measurements made by the receiver antennas that would be obtained with an estimated formation electrical characteristic; calculating an error using the error equation for an initial estimated value of the wave vector that comprises a term having a first number multiplied times a second number of radians to provide a plurality of calculated errors; and determining a minimum error from the plurality of calculated errors to estimate the electrical character

Abstract: A method for increasing sensitivity in a measurement of at least one of magnitude and direction of resistivity in a subsurface material, the method including: performing a first set of measurements of resistivity of the subsurface material using a first logging instrument; constructing a model of a background signal using the first set of measurements; calculating a predicted response of a second logging instrument to the model of the background signal; performing a second set of measurements of at least one of magnitude and direction of resistivity of the subsurface material using the second logging instrument; deriving a second logging instrument response from the second set of measurements; and subtracting the predicted response from the second logging instrument response to produce a corrected response that has greater sensitivity than the second logging instrument response.

Abstract: A phase error in measurements made by a resistivity logging tool is estimated by positioning the tool above a conducting surface. Deviation of the measured phase difference between the transmitter and the receiver from 90° gives the phase error in the electronics. It is emphasized that this abstract is provided to comply with the rules requiring an abstract which will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims.

Abstract: A method for increasing sensitivity in a measurement of at least one of magnitude and direction of resistivity in a subsurface material, the method including: performing a first set of measurements of resistivity of the subsurface material using a first logging instrument; constructing a model of a background signal using the first set of measurements; calculating a predicted response of a second logging instrument to the model of the background signal; performing a second set of measurements of at least one of magnitude and direction of resistivity of the subsurface material using the second logging instrument; deriving a second logging instrument response from the second set of measurements; and subtracting the predicted response from the second logging instrument response to produce a corrected response that has greater sensitivity than the second logging instrument response.

Abstract: Resistivity measurements are made at a plurality of frequencies. An asymptotic high-frequency limit is determined and the electrical efficiency is estimated as a ratio of the high frequency resistivity limit to the low frequency resistivity. From the electrical efficiency, petrophysical parameters of a rock such as porosity and water saturation can be estimated.

Abstract: Resistivity measurements are made at a plurality of frequencies. An asymptotic high-frequency limit is determined and the electrical efficiency is estimated as a ratio of the high frequency resistivity limit to the low frequency resistivity. From the electrical efficiency, petrophysical parameters of a rock such as porosity and water saturation can be estimated.

Abstract: A phase error in measurements made by a resistivity logging tool is estimated by positioning the tool above a conducting surface. Deviation of the measured phase difference between the transmitter and the receiver from 90° gives the phase error in the electronics. It is emphasized that this abstract is provided to comply with the rules requiring an abstract which will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims.

Abstract: Cross-component measurements made at a plurality of toolface angles are processed to remove bias. The amplitude of the resulting sinusoid is used to estimate a distance to an interface in an earth formation.

Abstract: Resistivity measurements are made at a plurality of frequencies. An asymptotic high-frequency limit is determined and the electrical efficiency is estimated as a ratio of the high frequency resistivity limit to the low frequency resistivity. From the electrical efficiency, petrophysical parameters of a rock such as porosity and water saturation can be estimated.

Abstract: Resistivity measurements are made at a plurality of frequencies. An asymptotic high-frequency limit is determined and the electrical efficiency is estimated as a ratio of the high frequency resistivity limit to the low frequency resistivity. From the electrical efficiency, petrophysical parameters of a rock such as porosity and water saturation can be estimated. It is emphasized that this abstract is provided to comply with the rules requiring an abstract which will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims.

Abstract: The present invention provides a measurement-while-drilling (MWD) system having a downhole computer and multiple downhole sensors. Relatively large amounts of basic or “raw” data are measured by downhole sensors, and these data are processed within a downhole computer to be reduced to parameters of interest, which may be utilized to control the drilling operation by downhole devices, stored downhole, telemetered to the surface, or both. The measurements may be correlated downhole with stored reference data thereby providing additional information pertaining to the drilling operation. Downhole depth correlation between downhole measured parameters may be made by utilizing surface determined or downhole determined borehole depth.

Abstract: The present invention provides a measurement-while-drilling (MWD) system having a downhole computer and multiple downhole sensors. Relatively large amounts of basic or "raw" data are measured by downhole sensors, and these data are processed within a downhole computer to be reduced to parameters of interest, which may be utilized to control the drilling operation by downhole devices, stored downhole, telemetered to the surface, or both. The measurements may be correlated downhole with stored reference data thereby providing additional information pertaining to the drilling operation. Downhole depth correlation between downhole measured parameters may be made by utilizing surface determined or downhole determined borehole depth.