Abstract: A method to obtain gain-corrected measurements. A measurement tool having one or more arrays is provided, wherein the arrays include two co-located triaxial transmitters and two co-located triaxial receivers. Measurements are obtained using the transmitters and the receivers. Impedance matrices are formed from the obtained measurements and the impedance matrices are combined to provide gain-corrected measurements. The apparatus may alternatively be a while-drilling logging tool having one or more arrays, wherein each array comprises a transmitter, a receiver, and a buck, and wherein the signal received by the receiver is subtracted from the signal received by the buck or vice versa. A slotted shield may be incorporated into either embodiment of the tool. The slots may form one or more island elements. A material is disposed in the slots. The islands and shield body have complementary tapered sides that confine the islands within the shield body.

Abstract: A method for integrating graphical logging content of a subterranean wellbore includes processing a plurality of digitized display images and relevant context information to generate a single synchronized display image including representations of each of the plurality of display image. The plurality of digitized display images and relevant context information are received at a central processor from a corresponding plurality of source tools or source processors. The display images are representative of subterranean wellbore conditions.

Abstract: An interactive display of results obtained from the inversion of logging data is produced by obtaining and inverting the logging data using a Monte-Carlo inversion. An interactive plot having a percentile scale plotted against a location parameter is produced and a particular percentile is selected using the interactive plot. A cross-section plot for the particular percentile using the results of the Monte-Carlo inversion is produced. The particular percentile can be a curve representing a best-fit solution or a polyline representing selected solutions. Background color/shading can be displayed on the interactive plot to indicate user-defined constraints have been applied. Uncertain features can be plotted on a corresponding cross-section display using fading. Clusters of solutions that are substantially equally likely, given the measurements at a particular drill location, can be identified and plotted.

Abstract: A method for integrating graphical logging content of a subterranean wellbore includes processing a plurality of digitized display images and relevant context information to generate a single synchronized display image including representations of each of the plurality of display image. The plurality of digitized display images and relevant context information are received at a central processor from a corresponding plurality of source tools or source processors. The display images are representative of subterranean wellbore conditions.

Abstract: A technique utilizes the acquisition of data from desired subterranean regions via a logging system. The logging system is constructed for use in a wellbore and comprises a transmitter module having a transmitter antenna. Additionally, the logging system utilizes a receiver module spaced from the transmitter module and having a receiver antenna. The transmitter antenna and the receiver antenna are oriented to enable sensitivity in desired directions, such as ahead of the logging system.

Abstract: A technique provides a methodology for improving surveys of subterranean regions. The methodology comprises estimating macro anisotropy and an intrinsic or micro anisotropy of an overburden. A surface electromagnetic survey is conducted, and the data from the survey is inverted based on or including information gained from estimating the macro anisotropy and/or intrinsic anisotropy. A processor system can be used to conduct the inversion with the adjustments for anisotropy to improve the information provided by the survey.

Abstract: The present disclosure relates to a method to determine the phase of a signal when transmitter and receiver circuits use separate clocks. A discrepancy between the separate clocks is determined, as is a correction factor between the separate clocks. The phase is determined using a measured time of arrival of the signal, the determined discrepancy, and the determined correction factor. A drift factor and an expected start time of a pulse sequence may be used to determine the discrepancy. A start time of a pulse within the pulse sequence is determined and used to determine the correction factor. The method works by either absolute synchronization of the separate clocks, or by making the measurements independent of clock synchronization.

Abstract: A method for directing borehole drilling in a target earth formation includes the following steps: providing drilling equipment having a bottom hole assembly that includes a controllable directional drilling subsystem, and a logging-while-drilling directional measurement tool with a look-around and look-ahead capability; determining the presence of a predetermined type of formation characteristic in the target formation; and navigating a drill path in the target formation with the drilling equipment, including receiving measurement signals from the directional measurement tool, obtaining, from the received measurement signals, indications of formation parameters with respect to the formation characteristic in the target formation, and controlling the directional drilling subsystem to drill in a direction determined as a function of the obtained indication of formation parameters.

Abstract: The present disclosure relates to a method to determine a formation property of a subsurface formation. A downhole logging tool having two or more antennas, at least two of the antennas having a transversely-sensitive element and an axially-sensitive element is provided. Azimuthally-sensitive measurements are obtained using the antennas of the downhole logging tool. The measurements are fitted to a Fourier series having Fourier coefficients that include channel gains, if any. A DC component, a first harmonic component, and a second harmonic component are determined from the Fourier series, a measurement type is determined using the DC component, the first harmonic component, and/or the second harmonic component, and the formation property of the subsurface formation is determined using the determined measurement type.

Abstract: During a drilling operation, measured data from the drilling operation may be received with a panistic inversion and risk estimate module. The panistic inversion and risk estimate module may generate a plurality of mathematical solutions from a panistic inversion that uses the measured data and one or more earth models. The one or more earth models having various parameters may be selected prior to drilling and/or while the drilling operation occurs. For each solution of the plurality of mathematical solutions generated from the panistic inversion, the panistic inversion and risk estimate module may determine if the measured data exceeds one or more probability risk thresholds associated with the drilling operation. If the measured data exceeds the probability risk threshold associated with the drilling operation, then the panistic inversion and risk estimate module may generate an alert.

Abstract: A technique provides a methodology for improving surveys of subterranean regions. The methodology comprises estimating macro anisotropy and an intrinsic or micro anisotropy of an overburden. A surface electromagnetic survey is conducted, and the data from the survey is inverted based on or including information gained from estimating the macro anisotropy and/or intrinsic anisotropy. A processor system can be used to conduct the inversion with the adjustments for anisotropy to improve the information provided by the survey.

Abstract: A technique utilizes the acquisition of data from desired subterranean regions via a logging system. The logging system is constructed for use in a wellbore and comprises a transmitter module having a transmitter antenna. Additionally, the logging system utilizes a receiver module spaced from the transmitter module and having a receiver antenna. The transmitter antenna and the receiver antenna are oriented to enable sensitivity in desired directions, such as ahead of the logging system.

Abstract: A resistivity array having a modular design includes a transmitter module with at least one antenna, wherein the transmitter module has connectors on both ends adapted to connect with other downhole tools; and a receiver module with at least one antenna, wherein the transmitter module has connectors on both ends adapted to connect with other downhole tools; and wherein the transmitter module and the receiver module are spaced apart on a drill string and separated by at least one downhole tool. Each transmitter and receiver module may comprise at least one antenna coil with a magnetic moment orientation not limited to the tool longitudinal direction. A spacing between the transmitter and receiver module may be selected based on expected reservoir thickness.

Abstract: A logging tool and method to make subsurface measurements is disclosed, wherein the tool is placed within a borehole penetrating a formation. The tool has a transmitter antenna and a receiver antenna spaced apart along a longitudinal axis of the tool, and at least one of the transmitter or receiver antennas has a dipole moment that is non-coaxial with the longitudinal axis of the tool. The at least one non-coaxial antenna can rotate relative to the other antenna. Energy is transmitted from the transmitter antenna and a signal associated with the transmitted energy is measured at the receiver antenna while the at least one non-coaxial antenna rotates relative to the other antenna.

Abstract: A technique provides a methodology for improving surveys of subterranean regions. The methodology comprises estimating macro anisotropy and an intrinsic or micro anisotropy of an overburden. A surface electromagnetic survey is conducted, and the data from the survey is inverted based on or including information gained from estimating the macro anisotropy and/or intrinsic anisotropy. A processor system can be used to conduct the inversion with the adjustments for anisotropy to improve the information provided by the survey.

Abstract: The present disclosure relates to a method to determine a clock signal when separate clocks are used. In one embodiment, a disciplined clock system comprising an update subsystem and a synthesis subsystem is provided. A first clock phase estimate is provided to the update subsystem and used, along with the update subsystem, to determine a frequency offset estimate and a phase offset estimate. The clock signal is determining using the frequency offset estimate, the phase offset estimate, and the synthesis subsystem. Alternatively, two clocks can be synchronized by generating a signal associated with a first clock; modulating the signal; transmitting the modulated signal; receiving the modulated signal by a receiver associated with a second clock; correlating the received signal; determining the time of arrival of the received signal; determining the time difference between the two clocks; and synchronizing the two clocks.

Abstract: A method and system for producing look-ahead profiles measurements includes positioning an energy transmitter, such as a transmitting antenna, proximate to a borehole assembly tool. One or more energy receivers, such as receiving antennas, are positioned along a length of the borehole assembly. Next, energy is transmitted to produce look-ahead scans relative to the borehole assembly tool. Look-ahead graph data with an x-axis being a function of a time relative to the position of the borehole assembly tool is generated. The look-ahead graph is produced and displayed on a display device. The look-ahead graph may track estimated formation values based on earth models. The estimated formation values are displayed below a tool position history line that is part of the look-ahead graph. The estimated formation values in the look-ahead graph may be based on inversions of resistivity data from the look-ahead scans.

Abstract: A method and a downhole tool determine one or more parameters of a formation traversed by a borehole where at least a portion of the formation has substantially parallel boundaries. A tool is disposed in the borehole that includes a transmitter having a dipole moment at an angle ?T with respect to a longitudinal axis of the tool, a receiver having a dipole moment at an angle ?R with respect to the longitudinal axis of the tool and a rotational position indicator. The transmitter-receiver pair transmits an electromagnetic signal while rotating the tool, receives the electromagnetic signal to produce a measured signal, and determine(s) the formation parameters for the portion of the formation having substantially parallel boundaries based on the measured signal.

Abstract: A technique utilizes the acquisition of data from desired subterranean regions via a logging system. The logging system is constructed for use in a wellbore and comprises a transmitter module having a transmitter antenna. Additionally, the logging system utilizes a receiver module spaced from the transmitter module and having a receiver antenna. The transmitter antenna and the receiver antenna are oriented to enable sensitivity in desired directions, such as ahead of the logging system.

Abstract: A technique provides a methodology for improving surveys of subterranean regions. The methodology comprises estimating macro anisotropy and an intrinsic or micro anisotropy of an overburden. A surface electromagnetic survey is conducted, and the data from the survey is inverted based on or including information gained from estimating the macro anisotropy and/or intrinsic anisotropy. A processor system can be used to conduct the inversion with the adjustments for anisotropy to improve the information provided by the survey.