Abstract: A system and method for determining formation parameters is provided. The system includes an induction logging tool having a plurality of transmitter coils. The induction logging tool further includes a plurality of receiver coils, each of the receiver coils being spaced apart from the transmitter coils by a predetermined distance and receiving a response signal from the formation. The system includes circuitry coupled to the induction logging tool, the circuitry determining voltages induced in the plurality of receiver coils by the response signal. The circuitry separates real or in-phase portions of the determined voltages from imaginary of ninety degrees out of phase portions of the determined voltages and determines formation parameters using imaginary portions of the measured voltages.

Abstract: A method and a system for determining metal loss in a layered system. The method may comprise disposing an EM metal loss tool downhole, broadcasting an electromagnetic field from the one or more transmitters of the EM metal loss tool into the layered system, recording the altered electromagnetic field with the one or more receivers, processing the signal with an information handling system, and determining metal loss in the layered system. A system may comprise an EM metal loss tool. The EM electromagnetic metal loss tool may comprise at least one transmitter and at least one receiver. The system may further comprise a conveyance, wherein the conveyance is attached to the electromagnetic metal loss tool, and an information handling system, wherein the information handling system is configured to process the altered electromagnetic field and determine metal loss in the layered system.

Abstract: Systems and methods for corrosion detection of downhole tubulars.

Abstract: Various disclosed borehole imaging tools and methods provide an improved high-resolution electrode configuration suitable for imaging in both water-based and oil-based muds. In at least some embodiments, the imaging tools employ a unitary conductive body to provide a wall-contacting face with grooves that define multiple sensing surfaces. Toroids may be seated in the grooves around each sensing surface for measuring the current flow through each sensing surface. Such placement enables a nearly ideal equipotential surface to be maintained and a straightforward “full coverage” electrode configuration due to a minimal electrode separation. Moreover, the disclosed configuration promises robust and reliable performance in the hostile conditions often experienced by logging while drilling (LWD) tools. This wall-contacting face can be provided on an extendable sensor pad or embedded on the outer surface of a LWD stabilizer fin.

Abstract: A method and system for location a collar. A method for locating a collar may comprise disposing a logging tool within a plurality of concentric pipes in a wellbore, measuring one or more wellbore parameters, creating a corrosion detection tool log from the measuring one or more wellbore parameters, processing the corrosion detection tool log to determine a location and a position of a plurality of collars on the concentric pipes, and adjusting the corrosion detection tool log to account for the location and position of the plurality of collars. A system for locating a collar may comprise a conveyance line, a logging tool, and an information handling system. The information handling system may be capable to measure one or more wellbore parameters, create a corrosion detection tool log from the measuring one or more wellbore parameters, and document the location and the position of the plurality of collars.

Abstract: A logging tool having a transmitter and receiver is positioned in a geological formation. While the logging tool is static, a transmit input signal is applied to a transmitter to cause the transmitter to induce a transmit output signal in the form of an electromagnetic field into a formation. While the logging tool is static, a formation signal is received based on the transmit output signal. The formation signal may be a voltage indicative of an induced polarization in the formation based on the transmit output signal. A complex resistivity of the formation is determined based on the formation signal.

Abstract: In some embodiments, an apparatus and a system, as well as a method and an article, may operate to estimate a value for a mud cake parameter to provide an estimated mud cake parameter value; to generate, in a solution operation, a formation parameter value and an adjusted mud cake parameter value using the estimated mud cake parameter value; and to provide corrected galvanic tool resistivity measurements based on at least the adjusted mud cake parameter value. Additional apparatus, systems, and methods are disclosed.

Abstract: Apparatus and techniques are described, such as for obtaining information indicative of a formation resistivity near a casing, such as using an array laterolog apparatus. For example, raw measurements received from a well tool in a borehole near a casing may indicate a resistivity of a geologic formation through which the borehole extends. Any errors or interference in the raw measurements caused by the proximity of the well tool to the casing may be removed to eliminate the casing effect on the raw measurements. In some examples, a signal and formation libraries that include casing specific parameters may be used in conjunction with non-casing optimized signal and formation libraries to perform correction mapping of raw measurements. The corrections and their application to the raw measurements may be based on the position of a well logging tool with respect to a casing termination point.

Abstract: A method and system for estimating a mud angle. A method may comprise disposing a downhole tool into a borehole, energizing a button array, transmitting a current from the electrode into a formation, recording the current from the formation with a return electrode to obtain a plurality of measurements, identifying at least one low resistivity zone from the plurality of measurements to produce a measurement set, inverting the measurement set to find a mud angle vector, removing the mud angle vector from the measurement set to obtain a corrected measurement, and obtaining an electrical image using the corrected measurement. A system may comprise a downhole tool, a conveyance, and an information handling system. The downhole tool may further comprise at least one electrode and at least one return electrode.

Abstract: A method and system for resistivity imaging. A method may comprise disposing a downhole tool into a borehole, applying a voltage difference between the array of injector electrodes, constructing a first set of formation images for each of the plurality of frequencies, applying a mud effect removal algorithm to produce a second set of formation images for each of the plurality of frequencies, applying a dielectric correction algorithm to each of the plurality of frequencies to produce a third set of formation images for each of the plurality of frequencies, and combining the first set of formation images, the second set of formation images, and the third set of formation images to obtain a blended image. A system for resistivity imaging may comprise a downhole tool. The downhole tool may comprises a pad, an array of injector electrodes, and one or more return electrodes.

Abstract: A method and system for determining location of a collar in a wellbore. A method may comprise taking an electromagnetic measurement, producing an electromagnetic log from the electromagnetic measurement, wherein the electromagnetic log comprises a plurality of channels, and locating a position of the collar in the electromagnetic log based on a collar signature in the electromagnetic log. A system may comprise an electromagnetic logging tool. The electromagnetic logging tool may comprise at least one receiver and at least one transmitter. The system may further comprise a conveyance and an information handling system, wherein the information handling system is configured to receive an electromagnetic measurement from the electromagnetic logging tool, produce an electromagnetic log from the electromagnetic measurement, wherein the electromagnetic log comprises at least one channel, and locate a position of a collar in the electromagnetic log with a collar signature.

Abstract: Described are tools, systems, and methods for dielectric logging using transient waveforms. In some embodiments, one or more microstrip antennas are employed for the measurements. In various embodiments, the waveforms are processed in the time-domain to determine the dielectric properties of a formation, from which geophysical formation properties can then be derived. Further embodiments are disclosed.

Abstract: The present disclosure relates generally to a system and method for increasing the reliability and data-rate transmission of information from a downhole device to the surface and from the surface to the downhole device. A fluid sampling system may comprise a downhole tool positionable in a wellbore and comprising a fluid testing chamber. The downhole tool may also comprise a light spectrum analysis unit disposed at a surface of the wellbore, wherein the light spectrum analysis unit comprises a detector. The downhole tool may further comprise a fiber optic cable for carrying light from the downhole tool to the light spectrum analysis unit, wherein the fiber optic cable is connected to the downhole tool and the light spectrum analysis unit.

Abstract: Apparatus, systems, and methods may operate to correct measured voltage data for selected weak differential measurements to provide corrected voltage data. Additional activity may include adjusting the corrected voltage data to remove level shifts in the measured voltage data caused by downhole tool impedance to provide adjusted voltage data, converting the adjusted voltage data into apparent resistivity data, inverting the apparent resistivity data to determine true resistivity values for a geological formation, and operating a controlled device according to the true resistivity values for the geological formation. Additional apparatus, systems, and methods are disclosed.

Abstract: Apparatus and methods can be implemented to monitor the condition of the production and intermediate casing strings in oil and gas field operations. A series of measurements can be made in a multi-pipe structure and received responses can be operated on by employing a mapping optimization procedure in which a surrogate model is updated. Estimates of one or more properties of the pipes of the multi-pipe structure can be generated using coefficients of the updated surrogate model. Additional apparatus, systems, and methods are disclosed.

Abstract: A method and system for determining location of a collar in a wellbore. A method may comprise taking an electromagnetic measurement, producing an electromagnetic log from the electromagnetic measurement, wherein the electromagnetic log comprises a plurality of channels, and locating a position of the collar in the electromagnetic log based on a collar signature in the electromagnetic log. A system may comprise an electromagnetic logging tool. The electromagnetic logging tool may comprise at least one receiver and at least one transmitter. The system may further comprise a conveyance and an information handling system, wherein the information handling system is configured to receive an electromagnetic measurement from the electromagnetic logging tool, produce an electromagnetic log from the electromagnetic measurement, wherein the electromagnetic log comprises at least one channel, and locate a position of a collar in the electromagnetic log with a collar signature.

Abstract: Systems and methods for reducing effects of pipe couplings in electromagnetic log data. A method for corrosion detection comprises disposing an electromagnetic logging tool within a plurality of concentric pipes in a wellbore; obtaining electromagnetic log data along the concentric pipes; and identifying a location of at least one pipe coupling on at least one of the concentric pipes; and processing the electromagnetic log data to determine one or more attribute of the concentric pipes as a function of depth, wherein the processing uses the location of at least one pipe coupling to account for effect of the at least one pipe coupling on the electromagnetic log data.

Abstract: Apparatus and methods can be conducted in a multi-pipe structure to determine eccentricity of one or more pipes of the multi-pipe structure. A tool having a center axis as a symmetry axis of the tool can be used in which receivers are arranged as a number of pairs of receivers around the center axis of the tool. Each receiver of a pair can be disposed opposite the other receiver of the pair with respect to the center axis such that each pair is symmetrical with respect to the center axis of the tool. Eccentricity of one or more pipes of the multi-pipe structure can be determined based on the received responses at the receivers of the pairs.

Abstract: A method includes deploying an electromagnetic (EM) defect detection tool in a borehole having one or more tubular strings. The method also includes collecting measurements by the EM defect detection tool as a function of measured depth or position. The method also includes using the measurements and a first inversion process to determine a defect in the one or more tubular strings. The first inversion process involves a cost function having a misfit term and having a stabilizing term with nominal model parameters. The method also includes performing an operation in response to the determined defect.

Abstract: A system includes a tool to dispose in a wellbore lined with pipe. The tool includes first and second receiver coils having a non-uniform winding along a longitudinal axis, a third receiver coil having a non-uniform winding coaxial with at least one of the first and second receiver coils, and a transmitter. The system includes a processor to execute instructions to perform operations including causing the transmitter to emit an induced magnetic field, measuring the induced magnetic field using the first receiver coil to create a first measurement and using the first and second receiver coils to create a second measurement. The operations include determining a static magnetic field, selecting the first or second measurement based on a magnitude of the static magnetic field to determine a selected measurement, and determining at least one property of the pipe using the selected measurement.