Abstract: The disclosed embodiments include downhole electromagnetic reservoir monitors, and systems and methods to monitor downhole reservoirs. In one embodiment, the electromagnetic reservoir monitor includes a galvanic transmitter deployed proximate a wellbore casing and having a source electrode and a return electrode, where a current flowing from the source electrode, through a formation, to the return electrode is altered by a fluid reservoir of the formation, and where an altered component of the current induces a secondary magnetic field. The electromagnetic reservoir monitor also includes a magnetic receiver having a tilted coil deployed proximate the wellbore casing, the tilted coil having an orientation relative to a cross sectional plane normal to a longitudinal axis of the wellbore casing, and the tilted coil operable to detect a component of the secondary magnetic field, where the secondary magnetic field is indicative of at least one property of the fluid reservoir.

Abstract: Various embodiments include apparatus and methods implemented to monitor detection of a flood front of a waterflood in a formation. Embodiments can include control of current in a set of three current electrodes to inject current into a formation around a pipe in a wellbore, where the three current electrodes include two of the electrodes to inject current and the third electrode to operatively provide a current return. Response of the formation to the current injections can be communicated by interrogating an optical fiber that extends along a longitudinal axis of the pipe. Determination of progression of the waterflood with respect to the wellbore can be provided from controlling the current and interrogating the optical fiber over time. Additional apparatus, systems, and methods are disclosed.

Abstract: A method and system for determining properties of a pipe string using multi-channel induction measurements. The method may comprise disposing a multi-channel induction tool in a cased hole, obtaining a multi-channel measurement, forming a log from the multi-channel measurement, extracting at least one abnormality that corresponds to known metal thickness, performing a search to find a set of pipe material properties that minimize a mismatch between the abnormality and a simulated response, and inverting the log to estimate the set of pipe material properties at one or more depth points using the set of pipe material properties. The system may comprise a multi-channel induction tool. The multi-channel induction tool may comprise at least one transmitter, at least one receiver, and an information handling system.

Abstract: The disclosed embodiments include an acoustic noise reduction device. In one embodiment, the device includes a first sensor operable to detect a first acoustic noise signal and a desired signal and to modulate a first plurality of optical signals in response to detecting at least one of the first acoustic noise signal and the desired signal. The device also includes a second sensor operable to detect a second acoustic noise signal and modulate a second plurality of optical signals in response to detecting the second acoustic noise signal. The device further includes a coupler that is connected to the first and second sensors, where components of the modulated first and second plurality of optical signals approximately cancel each other out.

Abstract: A method for three dimensional visualization and manipulation of downhole data. A measured signal is received a downhole environment and a three dimensional virtualization of the measured signal is generated. A stereographic viewer displays the three dimensional virtualization of the measured signal. The three dimensional virtualization can be manipulated in response to an input from a user, thereby creating a manipulated three dimensional virtualization. The stereographic viewer can display the manipulated three dimensional virtualization.

Abstract: A disclosed downhole drilling system may include a drill bit electrically coupled to a pulse-generating circuit to generate electrical arcs between first and second electrodes during pulsed drilling operations, a sensor to record responses to electromagnetic or acoustic waves produced by the electrical arcs, and a sensor analysis system. The electrical arcs occur at different azimuthal locations between the electrodes. The sensor analysis system may obtain a plurality of measurements representing first responses recorded by the sensor during a pulsed drilling operation, generate a model of a source of the electrical arcs based on the measurements, obtain an additional measurement representing a second response recorded by the sensor during the operation, and determine a characteristic of a formation near the drill bit using an inversion based on the model and the additional measurement. The determined characteristic may be used to determine dip parameters or construct images of the formation.

Abstract: In accordance with at least one aspect of this disclosure, a signal arithmetic processor includes a fiber optic cable including a fiber optic input and a fiber optic output and two or more electro-optical transducers coupled to the fiber optic cable between the fiber optic input and output and having at least a first electrode and second electrode, the two or more electro-optical transducers configured to modify an optical signal in the fiber optic cable based on a voltage between the first electrode and the second electrode of the two or more electro-optical transducers. The signal arithmetic processor can also include an interferometer coupled to the fiber optic cable and configured to sense a phase difference of a fiber optic signal between the fiber optic input and the fiber optic output.

Abstract: A method and system for visualizing data to detect a collar. A method may comprise disposing an electromagnetic logging tool downhole; emitting an electromagnetic field from the transmitter; energizing a casing with the electromagnetic field to produce an eddy current; recording the eddy current from the casing with the receiver; creating a variable-density-log from the recorded eddy current; selecting a wrapping period for the variable-density-log; creating a wrapped-variable-density-log from the variable-density-log using the wrapping period; and determining at least one collar location and a pipe index with the wrapped-variable-density-log. A system for to detect a collar may comprise an electromagnetic logging tool. The electromagnetic logging tool may comprise a transmitter and a receiver, wherein the transmitter and the receiver may be a coil. The system may further comprise an information handling system.

Abstract: An electromagnetic induction tool and method. The electromagnetic induction tool may comprise a tool body, a gap sub may separate different sections of the tool body and may be positioned to at least partially hinder the flow of an axial current and an azimuthal current on the tool body. A coil antenna may be disposed over the gap sub. A method of increasing an electromagnetic field may comprise providing an electromagnetic induction tool. The electromagnetic induction tool may comprise a tool body, a gap sub may separate different sections of the tool body and may be positioned to at least partially hinder flow of an axial current and an azimuthal current on the tool body. A coil antenna may be disposed over the gap sub. The method may further comprise placing the electromagnetic induction tool into a wellbore and operating the coil antenna.

Abstract: A downhole drilling system is disclosed. The downhole drilling system may include a pulse-generating circuit, a drill bit including a first pair of electrodes electrically coupled to the pulse-generating circuit to receive a first electrical pulse from the pulse-generating circuit and form a first electrical arc between the first pair of electrodes during a pulsed drilling operation; a sensor to record responses to the first electrical pulse during the pulsed drilling operation; and a sensor analysis system communicatively coupled to the sensor, the sensor analysis system configured to obtain a first measurement from the sensor representing the responses recorded by the sensor during the pulsed drilling operation, and determine a first value of the dielectric constant associated with a portion of a formation in proximity to the drill bit, the first value of the dielectric constant based on the first measurement.

Abstract: A method and system for wellbore ranging. A method for wellbore ranging may comprise placing a coil antenna in a wellbore, wherein the coil antenna may comprise one or more coil windings, and the coil windings comprise a magnetic material. The method may further comprise measuring a characteristic of an induced electromagnetic field with the coil antenna. A system for wellbore ranging may comprise an electromagnetic ranging tool which may further comprise a coil antenna, wherein the coil antenna comprises one or more coil windings, and wherein the coil windings comprise a magnetic material. The method may further comprise an information handling system, wherein the information handling system may be operable to measure a characteristic of an induced electromagnetic field with the coil antenna.

Abstract: A method for detecting corrosion may comprise placing an electromagnetic logging tool into a wellbore, emitting an electromagnetic field from a transmitter, energizing a casing with the electromagnetic field to produce an eddy current, recording the eddy current from the casing with a receiver, creating a well log from the recorded eddy current, removing a collar signal from the well log to obtain a collar-removed signal, calculating a baseline signal from the collar-removed signal, subtracting the baseline signal from the collar-removed signal to obtain a baseline-subtracted signal, calculating an artifact-removed signal with the baseline-subtracted signal, and displaying the artifact-removed signal. A system for detecting corrosion may comprise an electromagnetic logging tool, wherein the electromagnetic logging tool comprises a transmitter and a receiver. The system may further comprise an information handling system.

Abstract: A method comprising: disposing an induction tool in a cased hole, wherein the induction tool comprises a transmitter and a receiver; broadcasting electromagnetic fields from the transmitter into a subterranean formation to form an eddy current; recording the eddy current with the receiver to produce induction measurements; obtaining a log comprising at least one channel from the induction measurements; constructing an inversion cost functional comprising a misfit term and a regularization term; performing a first inversion using the inversion cost functional to estimate pipe properties at a first plurality of depth points; optimizing the inversion cost functional such that the estimated pipe properties at the first plurality of depth points minimize an objective functional; performing a second inversion using the optimized inversion cost functional to estimate pipe properties at a second plurality of depth points; and displaying the pipe properties at the second plurality of depth points to a user.

Abstract: Systems and methods for incorporating mandrel current measurements in deep ranging inversion. A method may include introducing a current through a transmitter into a subterranean formation, wherein the transmitter may be a component of an electromagnetic induction tool disposed in a wellbore, wherein the electromagnetic induction tool may comprise the transmitter, a toroid receiver, and a second receiver comprising a coil or electrode, wherein the transmitter, the toroid receiver, and the second receiver may be disposed on a tubular; measuring a first signal utilizing the toroid receiver, wherein the first signal may comprise a tubular current; measuring a second signal utilizing the receiver and determining at least one downhole parameter utilizing the first signal and the second signal.

Abstract: A method for determining the activation of an expandable sand screen may comprise disposing an electromagnetic (EM) detection tool into a wellbore. The EM detection tool may comprise at least one transmitter and at least one receiver. The method may further comprise transmitting an EM field from the one or more transmitters into the expandable sand screen to energize the expandable sand screen and form an eddy current, recording a voltage of the eddy current with the at least one receiver, and determining an activation state of the expandable sand screen based at least partially on the voltage of the eddy current.

Abstract: A method and system for mitigating direct coupling. A method of mitigating direct coupling may comprise disposing an electromagnetic sensor system in a wellbore. The electromagnetic sensor system may include a receiver disposed on a conductive body and a gap sub disposed at another location on the conductive body. Exciting an electromagnetic source to inject an electrical current into a formation. Exciting the gap sub to achieve a small current condition at the selected point. Performing a first measurement at a receiver. Interpreting the first measurement to calculate a formation or pipe parameter and using the formation or pipe parameter to adjust at least one parameter of a well operation. A system of mitigating direct coupling may include a conductive body may comprise a gap sub, a controller, a voltage source, a receiver, and an information handling system. The information handling system may be operable to cancel current.

Abstract: A method and system for identifying a target well. A system for identifying a target well may comprise placing an electromagnetic ranging tool in a wellbore, transmitting an electromagnetic field into a formation, inducing an eddy current within a target well, measuring a second electromagnetic field from the target well, calculating a position or an orientation of a transmitter or a receiver relative to another position, and calculating at least one parameter of the target well. An electromagnetic ranging system may comprise an electromagnetic ranging tool and an information handling system. The information handling system may be operable to calculate a position and/or an orientation of a transmitter or a receiver relative to another position on the electromagnetic ranging tool disposed on a borehole assembly, and calculate at least one parameter of a target well from the calculated position or orientation of the transmitter and the receiver.

Abstract: An apparatus includes a processor and a machine-readable medium having program code to cause the apparatus to obtain a first dictionary based on a first training set of signals and determine a first subset of the first training set of signals based on a training reconstruction accuracy threshold and the first dictionary, wherein each atom in the first dictionary includes at least one of a signal pattern and a function representing the signal pattern. The program code also includes code to generate a second dictionary based on a second training set of signals, wherein the second training set of signals includes the first subset of the first training set of signals.

Abstract: An apparatus includes a subsurface sensor for use in a borehole to provide a subsurface measurement series, a subsurface processor to receive the subsurface measurement series, and a machine-readable medium. The machine-readable medium has program code to cause the apparatus to obtain the subsurface measurement series and generate an atom combination based on the subsurface measurement series using the subsurface processor, wherein the atom combination comprises a subset of atoms from a dictionary. The code also has instructions to generate a set of characterizing values and transmit the set of characterizing values to a different physical location, wherein the set of characterizing values comprises an atom identifier and at least one corresponding atom weight for at least one atom from the atom combination.

Abstract: A method comprising: disposing an induction tool in a cased hole, wherein the induction tool comprises a transmitter and a receiver; broadcasting electromagnetic fields from the transmitter into a subterranean formation to form an eddy current; recording the eddy current with the receiver to produce induction measurements; obtaining a log comprising at least one channel from the induction measurements; constructing an inversion cost functional comprising a misfit term and a regularization term; performing a first inversion using the inversion cost functional to estimate pipe properties at a first plurality of depth points; optimizing the inversion cost functional such that the estimated pipe properties at the first plurality of depth points minimize an objective functional; performing a second inversion using the optimized inversion cost functional to estimate pipe properties at a second plurality of depth points; and displaying the pipe properties at the second plurality of depth points to a user.