Abstract: Systems and methods for smoothing a resistivity log are disclosed. An azimuthal resistivity tool measures azimuthal impedances at multiple azimuthal angles around a wellbore axis at each depth. It is determined whether the drill string was in a drilling mode or a sliding mode at the depth. If the drill string was in the drilling mode, a co-axial component and a lateral component are determined based in part on the azimuthal impedances associated with the depth and the lateral component is stored. If the drill string was in the sliding mode, a second co-axial component is determined based in part on at least one of the plurality of azimuthal impedances and a previously stored lateral component. The resistivity log is plotted from resistivities determined from the first and second co-axial components at each depth.

Abstract: A method comprises obtaining measurement data of a subsurface formation while drilling a wellbore in the subsurface formation. The method comprises generating a horizontal resistivity model of the subsurface formation at respective depths along the wellbore based on the measurement data. The method comprises generating a vertical resistivity model of the subsurface formation at the respective depths along the wellbore based on the measurement data. The method comprises generating an effective resistivity at the respective depths along the wellbore based on the horizontal resistivity model and the vertical resistivity model to indicate a formation resistivity in each direction of the wellbore. The method comprises performing a drilling operation based on the effective resistivity.

Abstract: In general, in one aspect, embodiments relate to a method and/or system for obtaining one or more measurements collected by a downhole tool at a wellbore depth and defining a piecewise-polynomial inversion model describing one or more formation parameters. Systems and methods herein may further be for performing an inversion on the piecewise-polynomial inversion model to determine one or more formation parameters of the inversion model, and adjusting a path of the downhole tool based at least in part on the or more formation parameters of the piecewise-polynomial inversion model.

Abstract: Some implementations may include a subassembly configured for attachment to a tubular in a borehole. The subassembly may include a tuning module configured to tune a first antenna to a first frequency based on a design requirement of the first antenna or a desired distance between the first antenna and a second antenna. The subassembly also may include the first antenna configured to transmit or receive a signal at the first frequency to or from the second antenna.

Abstract: A system and a method for a look-ahead drill bit. The system may comprise an ultra-deep transmitter operable to transmit a low frequency signal into a formation, a shallow tool operable to transmit a high frequency signal into the formation, at least one ultra-deep receiver operable to record a reflected low frequency signal, and at least one pair of collocated receivers, wherein the at least one pair of collocated receivers are operable to record a reflected high frequency signal. A method may comprise transmitting a high frequency signal from the shallow tool into the formation, transmitting a low frequency signal from the ultra-deep transmitter into the formation, evaluating the reflected high frequency signal and the reflected low frequency signal on an information handling system with a look-ahead inversion, and steering the bottom hole assembly in the formation based on the subterranean formation property.

Abstract: A system can calibrate inconsistencies in a wellbore tool. The system can receive a first set of measurements and a second set of measurements with respect to different electromagnetic antennas. The system can decouple a first multi-components tensor corresponding to the first set of measurements and a second multi-components tensor corresponding to the second set of measurements. The system can determine, using the decoupled first and second multi-components tensors, a scaling factor. The system can apply the scaling factor to a raw measurement received with respect to an electromagnetic antenna of the wellbore tool positioned in a wellbore to decouple a third multi-components tensor or to decoupled components of a fourth multi-components tensor for controlling a wellbore operation.

Abstract: System and methods for geosteering inversion are provided. Downhole tool responses are predicted for different points along a planned path of a wellbore during a downhole operation, based on each of a plurality of inversion models. Measurements of the downhole tool's actual responses are obtained as the wellbore is drilled over the different points during a current stage of the operation. The inversion models are clustered based on a comparison between the actual and predicted tool responses and a randomly selected centroid for each cluster. The inversion models are re-clustered using an average inversion model determined for each cluster as the centroid for that cluster. At least one of the re-m clustered inversion models is used to perform inversion for one or more subsequent stages of the downhole operation along the planned wellbore path. The planned wellbore path is adjusted for the subsequent stage(s) of the downhole operation.

Abstract: A system can calibrate inconsistencies in a wellbore tool. The system can receive a first set of measurements and a second set of measurements with respect to different electromagnetic antennas. The system can decouple a first multi-components tensor corresponding to the first set of measurements and a second multi-components tensor corresponding to the second set of measurements. The system can determine, using the decoupled first and second multi-components tensors, a scaling factor. The system can apply the scaling factor to a raw measurement received with respect to an electromagnetic antenna of the wellbore tool positioned in a wellbore to decouple a third multi-components tensor or to decoupled components of a fourth multi-components tensor for controlling a wellbore operation.

Abstract: A system and a method for evaluating a subterranean earth formation include a logging tool locatable in a wellbore dispose in the formation. The logging tool may include a transmitter antenna and a single receiver antenna. The transmitter antenna is configured to transmit a first electromagnetic signal into the subterranean earth formation. The system further includes a processor and a non-transitory memory device. The memory device includes instructions that cause the processor to control a current and a voltage sourced to the transmitter antenna, receive, via the single receiver antenna, a second electromagnetic signal emitted by the subterranean earth formation in response to receiving the first electromagnetic signal, and determine a resistivity of the subterranean earth formation based on the second electromagnetic signal.

Abstract: A method and/or system comprising: disposing a bottom hole assembly into a wellbore, wherein the bottom hole assembly comprises: a transmitter sub comprising a transmitter coil; a first receiver sub comprising a first receiver coil; transmitting an electromagnetic wave into a subterranean formation with the transmitter coil; receiving a plurality of response signals with the first receiver coil, wherein the plurality of response signals are from two or more depths and are formed from the electromagnetic wave interacting with the subterranean formation. Additionally, the method and/or system may be configured to analyze a gradient of the response signals to determine if the gradient exceeds a threshold, wherein the threshold indicates a presence of a fracture or fault.

Abstract: Some aspects relate to techniques for calibrating a logging tool. In some implementations, the logging tool may estimate certain unknown properties of a signal based on distances between transmitters and receivers of the logging tool and based on frequencies used by the transmitters and receivers. The logging tool may estimate the unknown properties by interpolating values into a mathematical function related to the above-noted distances and frequencies. After estimating the unknown properties, the logging tool may be deployed into the wellbore, where it may use the estimated properties to process signals received through a subsurface formation.

Abstract: Systems and methods of the present disclosure relate to calibration of resistivity logging tool. A method to calibrate a resistivity logging tool comprises disposing the resistivity logging tool into a formation; acquiring a signal at each logging point with the resistivity logging tool; assuming a formation model for a first set of continuous logging points in the formation; inverting all of the signals for unknown model parameters of the formation model, wherein the formation model is the same for all of the continuous logging points in the first set; assigning at least one calibration coefficient to each type of signal, wherein the calibration coefficients are the same for the first set; and building an unknown vector that includes the unknown model parameters and the calibration coefficients, to calibrate the resistivity logging tool.

Abstract: Borehole images can be corrected using machine-learning models. For example, a system can train a machine-learning model based on a training dataset. The training dataset can include a first set of borehole images correlated to a second set of borehole images, where the second set of borehole images are less precise versions of the first set of borehole images. The system can then execute the trained machine-learning model in relation to an input borehole image to receive a corrected borehole image as output from the trained machine-learning model. The corrected borehole image can be a visually corrected version of the input borehole image. The system may then perform one or more operations based on the corrected borehole image, such as generating a graphical user interface that includes the corrected borehole image for display on a display device.

Abstract: A system and method for evaluating a subterranean formation includes a logging tool that includes transmitter and receiver antennae. The transmitter antenna transmits a first electromagnetic signal into the formation at a plurality of depths. The receiver antenna receives a plurality of second electromagnetic signals emitted by the formation in response to the first signal.

Abstract: A method and system for identifying a blind spot in one or more decoupled measurements. The method may comprise disposing an electromagnetic well measurement system into a wellbore. The electromagnetic well measurement system comprise an electromagnetic transmitter and a plurality of electromagnetic receivers. The method may further comprise transmitting electromagnetic fields into a formation with the electromagnetic transmitter, measuring the electromagnetic fields with the plurality of electromagnetic receivers as one or more measurements at one or more depths in the wellbore, decoupling the one or more measurements to form decoupled measurements, identifying if a blind spot is in the decoupled measurements, and performing an inversion with the decoupled measurements.

Abstract: A method includes detecting, via first and second receivers of a tool that are oriented at a first and a third tilt angle, respectively, a first and second measurement of a first signal transmitted by a transmitter of the tool that is oriented at a second tilt angle into a substantially non-conductive material. The method includes determining, based on the first and second measurements, a first tensor and conveying the tool into a first wellbore formed in a subsurface formation. The method includes detecting, via the first receiver and the second receiver, a third and fourth measurement, respectively, of a second signal transmitted by the transmitter and determining, based on the third and fourth measurements, a second tensor and determining a third tensor (having values independent of the first, second, and third tilt angles) based on a relationship between the first and second tensors.

Abstract: A system can calibrate inconsistencies in a wellbore tool. The system can receive a first set of measurements and a second set of measurements with respect to different electromagnetic antennas. The system can decouple a first multi-components tensor corresponding to the first set of measurements and a second multi-components tensor corresponding to the second set of measurements. The system can determine, using the decoupled first and second multi-components tensors, a scaling factor. The system can apply the scaling factor to a raw measurement received with respect to an electromagnetic antenna of the wellbore tool positioned in a wellbore to decouple a third multi-components tensor or to decoupled components of a fourth multi-components tensor for controlling a wellbore operation.

Abstract: Certain aspects of the present disclosure relate to calibrating a formation signal for a mixed set measurement device. A first air-hang response of a first measurement device for a tubular string associated with a drilling operation can be measured. A second air-hang response of a second measurement device for the tubular string associated with the drilling operation can be measured. The first air-hang response and the second air-hang response can be used to determine a mixed air-hang response of the mixed set measurement device. The mixed air-hang response can be used to calibrate a formation signal for the mixed set measurement device.

Abstract: System and methods for geosteering inversion are provided. Downhole tool responses are predicted for different points along a planned path of a wellbore during a downhole operation, based on each of a plurality of inversion models. Measurements of the downhole tool's actual responses are obtained as the wellbore is drilled over the different points during a current stage of the operation. The inversion models are then clustered using a weighted clustering approached in which a weighted score system is formulated to apply a standard deviation, number of models, and/or misfit of each cluster as key parameters, and used to evaluate the clusters accordingly. The corresponding scores are computed and used to select clusters. The planned wellbore path is adjusted for the subsequent stage(s) of the downhole operation.

Abstract: Some aspects relate to techniques for calibrating a logging tool. In some implementations, the logging tool may estimate certain unknown properties of a signal based on distances between transmitters and receivers of the logging tool and based on frequencies used by the transmitters and receivers. The logging tool may estimate the unknown properties by interpolating values into a mathematical function related to the above-noted distances and frequencies. After estimating the unknown properties, the logging tool may be deployed into the wellbore, where it may use the estimated properties to process signals received through a subsurface formation.