Abstract: Apparatuses and methods are described, such as for aligning downhole measurements. Apparatuses and methods include an arrangement of at least two tilted transmitters and at least one tilted receiver along a longitudinal axis of the tool. A first and second plurality of azimuthal measurements are processed to provide a first and a second plurality of higher order mode signals configured to be time-shifted.

Abstract: Technology for obtaining formation parameters of a geological formation includes measuring a resistivity image of the geological formation. The measured resistivity image is compared to a modelled resistivity image where the modelled resistivity image is generated based on estimated formation parameters. A cost function is calculated based on the measure resistivity image and the modelled resistivity image. The estimated formation parameters are adjusted based on minimizing the cost function in order to generate a set of final formation parameters that represents a modelled resistivity image having a smallest cost function.

Abstract: A dielectric tool, system, and method for determining properties of subterranean formations. A dielectric tool may comprise a tool body, a transmitter, a receiver, wherein the receiver is operable to measure formation dielectric response to the transmitter, and at least one of the transmitter or at least one of the receiver is operable to have a substantially radial magnetic dipole moment. A system may comprise a dielectric tool and an information handling system, wherein the information handling system is operable to determine properties of a subterranean formation based at least on the measured formation dielectric response.

Abstract: An illustrative permanent electromagnetic (EM) monitoring system including a casing string positioned inside a borehole penetrating a formation, a source electrode attached to the casing string, an electrically insulating layer on an outer surface of the source electrode that provides a capacitive coupling of the source electrode to the formation, a power supply coupled to the source electrode which injects electrical current into the formation via the capacitive coupling, and a processing unit that determines a formation property based on at least the current received by a return electrode.

Abstract: Downhole ranging from multiple wellbores. In one example, multiple transmitters and multiple receivers are disposed in multiple wellbores to exchange electromagnetic signals. By implementing a full compensation technique, a computer system determines multiple compensated signals. A compensated signal is determined from a signal received from a first wellbore and a second signal received from a second wellbore. In another example, a first transmitter is disposed in a first wellbore, a first receiver is disposed in a second wellbore, and either a second transmitter or a second receiver is disposed in either the first wellbore or the second wellbore. By implementing partial compensation techniques, a computer system determines compensated signals. Using the compensated signals, the computer system determines a position of a first wellbore relative to a second wellbore, and provides the position.

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: Certain logging method and system embodiments obtain multi-component signal measurements from an electromagnetic logging tool conveyed along a borehole through a formation, and invert the measurements for a single frequency using an anisotropic formation model having at least dip, horizontal and vertical resistivity, and horizontal and vertical permittivity, as parameters. A resulting log is provided to represent a position dependence of at least one of said parameters or a formation property derived from at least one of said parameters. Illustrative formation properties include water saturation, rock type, and presence of pyrite or other such materials having anisotropic polarization. Inversions may be performed on measurements acquired at other frequencies to determine a representative dispersion curve for further characterization of the formation.

Abstract: Methods and systems are included that relate to the detection and monitoring of defects in wellbore conduits using a distributed sensor system and a wireline transmitter. A method for inspection of wellbore conduits may comprise: running a wireline transmitter into a wellbore; generating an electromagnetic field using the wireline transmitter, wherein the electromagnetic field penetrates one or more conduits disposed in the wellbore, and wherein the electromagnetic field induces emission of at least one secondary electromagnetic field from the one or more conduits; generating at least one signal in response to the secondary electromagnetic field, wherein the at least one signal is generated using a distributed sensor system, and wherein the distributed sensor system comprises electromagnetic field sensors installed in the wellbore and distributed along the one or more conduits; and identifying a pipe electromagnetic or geometric property of the one or more conduits based on the at least one signal.

Abstract: A casing has a plurality of joints of pipe joined by a plurality of casing collars, and an outer surface. A high-frequency alternating current (AC) source electrically is coupled to the casing. A coating of insulating material covers the entire outer surface of the casing. The coating has an opening that exposes a casing portion. The casing and the coating of insulating material define a capacitive electrode having an impedance Zf with a magnitude |Zf| at the frequency of operation f of the high-frequency AC source. Zf is low enough to allow current from the high-frequency AC source to be injected from the casing through the coating of insulating material into a surrounding formation. The casing portion has a resistance R to direct current (DC) with a magnitude that is very large compared to |Zf|.

Abstract: A system for ranging between two wellbores where an emitter electrode and return electrode of a current injection system are disposed to drive a current to a conductive member within a target wellbore to create an electromagnetic field about the conductive member. The electromagnetic field is measured utilizing a sensor disposed in an investigative wellbore, which may be in the process of being drilled. In some embodiments, the emitter electrode and return electrode are positioned on the surface of a formation, spaced apart from one another with locations on the surface selected to optimize current, and therefore, the electromagnetic field, at a desired point along the conductive member. In some embodiments, one or both of the emitter electrode and return electrode are positioned in the target wellbore.

Abstract: Methods and systems are described that can be used for locating conductive bodies such as wellbore casing or piping disposed below the earth's surface. An electrical current can be excited in a conductive body in each wellbore in a given area to produce a magnetic field, and the magnetic field can be detected by a ranging tool. Location and current parameters can be determined for an estimated number of wellbores producing non-negligible contributions to the magnetic field, and the estimated number of wellbores can be adjusted until the number of contributing wellbores is determined. Location solutions can be returned for each of the contributing wellbores, and the location solutions can be employed to facilitate exploration of drilling applications such as well avoidance, well intersection and/or steam assisted gravity drainage (SAGD) steering operations.

Abstract: Disclosed are telemetry systems and methods that employ a plurality of electromagnetic transceivers disposed outside a well casing string at a corresponding plurality of depths along the casing string. Each transceiver includes one or more toroidal inductors circumferentially surrounding the casing string and inductively coupled thereto to allow signal transmission between transceivers via currents induced in the casing. In some embodiments, signals are relayed via a chain of transceivers to facilitate indirect communication between a surface facility and other transceivers located too deep for direct communication to the surface.

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 dielectric tool, system, and method for determining properties of subterranean formations. A dielectric tool may comprise a tool body, a transmitter, a receiver, wherein the receiver is operable to measure formation dielectric response to the transmitter, and at least one of the transmitter or at least one of the receiver is operable to have a substantially radial magnetic dipole moment. A system may comprise a dielectric tool and an information handling system, wherein the information handling system is operable to determine properties of a subterranean formation based at least on the measured formation dielectric response.

Abstract: A method for dipole modeling may comprise providing an electromagnetic induction tool comprising an electromagnetic antenna, disposing the electromagnetic induction tool in a wellbore, and activating the electromagnetic antenna. The method may further comprise producing a dipole array equivalent of the electromagnetic antenna, where the dipole array equivalent comprises at least two dipoles. Additionally, the method may comprise implementing the dipole array equivalent in a forward model within an inversion process, wherein the inversion process determines an electromagnetic property.

Abstract: A system and method according to which a downhole component positioned behind a casing is powered, the casing extending within an oil and gas wellbore that traverses a subterranean formation. Powering the downhole component may include inducing an electrical current to flow in the casing; permitting the electrical current to flow out of the casing to create a first potential difference between a first point and a second point spaced therefrom, the first and second points being located behind the casing; utilizing the first potential difference to store electrical power; and supplying the stored electrical power to the downhole component positioned behind the casing to thereby power the downhole component. The system may include a power source in electrical communication with the casing; a power harvester positioned behind the casing and in electrical communication with the downhole component; and a current return unit in electrical communication with the power source.

Abstract: Apparatus, systems, and methods for ranging operate to use a wireline active ranging system to initially determine a relative distance and relative direction from a first well (e.g., ranging well) to a second well (e.g., target well) and an EM azimuthal logging tool to maintain or adjust the distance from the target well while drilling the ranging well. Additional apparatus, systems, and methods are disclosed.

Abstract: This disclosure may relate to a system and method for calculating the mud angle from a downhole device. A method for estimating a mud angle may comprise: disposing a downhole tool into a borehole; extending an arm of the downhole tool to a first location, wherein a pad is disposed on the arm; taking a first impedance measurement with at least one button electrode, wherein the button electrode is disposed in a button array, wherein the button array is disposed on the pad; extending the arm to a second location; taking a second impedance measurement with the at least one button electrode; transmitting the first measurement and the second measurement to an information handling system; and estimating the mud angle from the first impedance measurement and the second impedance measurement with an information handling system.

Abstract: A tool, method, and system for evaluating integrity of one or more tubing strings in a wellbore with multiple tubing strings. The tool, method, and system may include a magnetic source that can radiate the tubing strings with at least one primary electromagnetic field, a sensor that can detect a secondary magnetic field produced by induced eddy currents in the tubing strings, and a magnetizer that can magnetize a portion of an inner-most tubing string in the wellbore such that the portion of the inner-most tubing string has an increased magnetic transparency to the primary and secondary fields when the magnetizer is enabled, where the magnetizer can include a static magnetic source, and a structure that magnetically couples the static magnetic source to the inner-most tubing string.