Abstract: A method for calibrating a resistivity-logging tool using air-hang calibration is provided. The method may include performing an air-hang measurement using the resistivity-logging tool and performing a first measurement decoupling operation on the air-hang measurement. The first measurement decoupling operation may include generating correcting factors based on a physical model and calculating an air-hang calibration matrix based on the correcting factors. Additionally, the method may include performing a formation measurement using the resistivity-logging tool and performing a second measurement decoupling operation on the formation measurement to generate a decoupled formation measurement matrix. Further, the method may include calibrating the resistivity-logging tool to generate a calibrated formation measurement matrix by subtracting the air-hang calibration matrix from the decoupled formation measurement matrix.

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 method may comprise: inserting into a wellbore penetrating a subterranean formation a tool comprising: a transmitter sub assembly comprising a transmitter; and a receiver sub assembly comprising a receiver; generating an electromagnetic wave at the transmitter; propagating the electromagnetic wave through the subterranean formation; receiving the electromagnetic wave in the receiver; generating a response signal in the receiver; calculating a distance to a bed boundary position in a TVDp direction, wherein the TVDp direction is a direction where an angle between the TVDp direction and a tool axis is equal to a tool inclination from a true vertical direction (TVD), wherein TVD is a direction with respect to gravity; calculating a distance to bed boundary in a TST direction, wherein the TST direction is a true stratigraphic thickness direction in a direction towards a bed boundary; calculating a distance to bed boundary in a TVD direction; generating a formation characterization comprising a visual representa

Abstract: A resistivity measuring tool used in a drillstring having a drill bit on a distal end for drilling a wellbore in a formation includes a tool body having a longitudinal axis, a transmitting antenna, and a receiving antenna. The receiving antenna includes an antenna body having a longer axis disposed longitudinally in the tool body, and a wire coil having a central axis disposed around the antenna body, wherein the wire coil central axis is substantially perpendicular to the longer axis of the antenna body, and wherein the wire coil is configured to generate a magnetic moment orthogonal to the tool body longitudinal axis. The transmitting antenna is configured to transmit electromagnetic energy into the formation and induce a voltage signal related to a parameter of the formation in the receiving antenna.

Abstract: A method for determining water-filled porosity and water salinity in a well includes obtaining complex dielectric permittivity of earth formations, either from dielectric measurements representative of well cores, or from dielectric well logs; selecting a dielectric mixing law for the index number m; plotting a m-th root of complex dielectric permittivity at a specified frequency in the complex domain, wherein m is an index number; determining a matrix permittivity, a water salinity, and a water-filled porosity based on the complex dielectric permittivity and the dielectric mixing law; and displaying the water salinity and the water-filled porosity.

Abstract: A system, in some embodiments, comprises: a drill string; a first receiver coil coupled to the drill string at a fixed tilt angle with respect to a longitudinal axis of the drill string; a second receiver coil coupled to the drill string at another fixed tilt angle with respect to the longitudinal axis of the drill string; and a processor coupled to the first and second receiver coils and configured to trigonometrically manipulate a response of the first receiver coil and a response of the second receiver coil to determine a response of a modeled receiver coil having a desired tilt angle with respect to the longitudinal axis of the drill string, wherein said responses are based on a subterranean formation layer.

Abstract: A system includes an electromagnetic logging tool that transmits an electromagnetic signal as the tool is conveyed along a borehole through a formation. The system further includes a processing system that measures a first signal level in response to the tool being at a first measured depth, determines a first conductance based on the first signal level, measures a second signal level in response to the tool being at a second measured depth greater than the first measured depth, the second measured depth and the first measured depth defining a formation interval there between, determines a second conductance based on the second signal level, and assigns a uniform resistivity value to the formation interval based on the first conductance and the second conductance.

Abstract: A decoding device is used to securely send corresponding data gathered from multiple underground sources to multiple users. The device comprises a signal receiving port connected to multiple bandwidth filters and further connected to internet access points that are assigned to end users for secure data access. The invention facilitates allowing the signal and data being transmitted through the formation of the earth to reach end users located nearby and significant distances away from the source of the transmission. A system and method utilizing the decoding device is provided.

Abstract: A logging method and system for imaging a subterranean formation intersected by a borehole. A magnetic dipole generates an electromagnetic field in the formation, and an electric field induced by the magnetic dipole is sensed. The electromagnetic field is sensitive to bed boundaries and other changes of formation characteristics, and becomes induced when encountering the changes. Monitoring the time and magnitude of field inducement yields information about the presence and location of the bed boundaries and target formations. The magnetic dipole is oriented transverse to the borehole axis, and measurements of the electric field take place in directions that include transverse to the orientation of the magnetic dipole and transverse to the borehole axis, parallel with the borehole axis, or both.

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: A system for locating water floods, in some embodiments, comprises: multiple transducers for coupling to a borehole casing to inject current into a formation within which the casing is disposed; and multiple electrodes, each of the electrodes coupled to a different one of the multiple transducers when coupled to the casing, wherein each of the multiple transducers is used to determine a potential between the casing and a corresponding one of the multiple electrodes to which the transducer is coupled, wherein the potentials from the multiple transducers are used to determine a water flood location.

Abstract: A drilling system includes a roller cone drill bit having a roller cone and at least one antenna loop disposed in the roller cone for detecting magnetic or electromagnetic waves indicative of a target, a resistivity, or a boundary of the subterranean formation, man-made structure, or object. The drilling system may utilize the antenna loop to determine resistivity measurements of a subterranean formation through which the drill bit is being drilled. The location of the antenna in the roller cone may enable increased look-ahead and look-around measurements. In addition, the location of the antenna in the roller cone may facilitate anisotropic resistivity measurements to aid in steering the drill string into a desired portion of the subterranean formation.

Abstract: An antenna assembly that includes a bobbin including arcuate first and second bobbin portions positioned about a tool mandrel. A protective layer is formed about the first and second bobbin portions, and a cover occludes a portion of an axially extending gap defined between the first and second bobbin portions to prevent the protective layer from extruding into the gap.

Abstract: Methods and systems for identifying a salinity gradient in a formation surrounding a bore of a subterranean well includes introducing an antenna assembly into the bore of the subterranean well. The antenna assembly has an elongated antenna body. An emitting antenna extends axially along an outer surface of the antenna body. A receiving antenna extends axially along the outer surface of the antenna body, the receiving antenna being spaced circumferentially apart from the emitting antenna. An electromagnetic interrogation wave is produced into the formation with the emitting antenna with a pulse duration of no greater than 0.01 seconds. A reflected wave is received with the receiving antenna. The amplitude of the reflected wave is analyzed to determine a distribution of chlorine ion concentration in the formation.

Abstract: A measurement tool configured to be run through a bore of a hydrocarbon well. The measurement tool includes a dielectric core, a controller disposed at a first end of the dielectric core, a first wire helically disposed about the dielectric core and extending from the controller to a first location a first distance from the controller, and a second wire helically disposed about the dielectric core and extending from the controller to a second location a second distance from the controller. The controller provides first and second input signals to the first and second wires, and receives first and second reflected signals from the first and second wires.

Abstract: A downhole tool includes a chassis having a bore formed axially-therethrough. An antenna is positioned radially-outward from the chassis. A collar is positioned radially-outward from the antenna. A window is defined radially-through the collar. An insert is positioned in the window. The insert is made at least partially of a ceramic material.

Abstract: A method to measure a parameter of interest is provided. The method includes receiving a first signal via an antenna of a reception circuit. The method further includes generating a second signal by a signal generator of the reception circuit. The method further includes mixing the first signal and the second signal in a mixer of the reception circuit to generate a third signal. The method further includes measuring a parameter of the third signal using an instrument. The method further includes adjusting, by a processor, a frequency of the second signal to substantially match a frequency of the first signal based at least in part on the measured parameter of the third signal. The method further includes determining, by the processor, the parameter of interest using the adjusted frequency of the second signal.

Abstract: Apparatus (10) for use in determining values of properties of n layers (16,17) of a borehole (11) formed in the Earth's crust (12) comprises a plurality of at least (2n-1) sensor members (19,21,22) of mutually differing, known or calculable, geometric factors, as defined with reference to a sample under investigation comprising n layers. The sensor members (19,21,22) are capable of detecting reflected or transmitted electromagnetic energy and the apparatus (10) includes one or more supports (24,26?) for supporting the sensor members (19,21,22) in a said borehole (11) adjacent and/or in contact with one or more said layers (16,17), the apparatus (10) being capable of causing transmission of electromagnetic energy along, and/or reflection of electromagnetic energy at, each sensor member (19,21,22) in a manner permitting the calculation of values of properties of such layers (16,17) based on reflected or transmitted energy values detected at the sensor members (19,21,22).

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: A downhole electromagnetic logging tool having two or more antenna groups spaced along a longitudinal axis of the logging tool, each antenna group having one antenna or multiple antennas proximally located or collocated, each antenna group having at least one tilted antenna, at least one antenna group having, in addition to the tilted antenna, at least one transverse or axial antenna, and any given pair of antenna groups comprising at least four antennas is disclosed. The logging tool is disposed in a wellbore penetrating a formation and, while rotating, measures a tool rotation angle, transmits an electromagnetic signal from one antenna group, and receives the electromagnetic signal with another antenna group. Elements of an electromagnetic coupling tensor are determined using the received electromagnetic signal and the measured tool rotation angle, and properties of the formation using one or more elements of the determined electromagnetic coupling tensor are inferred.

Abstract: The present invention provides a methodology and system for resistivity tool design. By using at least one E field antenna instead of magnetic antennas, stronger signals can be captured by a smaller system. The more effective antenna design of the present invention has broad applications in various tools including geosteering, look ahead, and triaxial induction.

Abstract: A data transmission system for use with a drill string in a primary wellbore is disclosed. The data transmission system includes a toroidal antenna assembly. The toroidal antenna assembly is disposed around the drill string at a primary downhole location within the primary wellbore and configured to transmit a signal from a transmitter. The signal corresponds to sensor data. The toroidal antenna assembly includes a plurality of toroidal antennas, wherein each toroidal antenna is configured to transmit the same signal from the transmitter. Because a plurality of toroidal antennas are utilized to transmit the same signal, construction of the drill string can be more mechanically robust than a conventional insulated gap collar while permitting reliable and fast transmission of sensor data to the surface.

Abstract: A wireless power transfer system may provide coils that are respectively position on upper and lower ends of a pipe to allow power to be wirelessly transferred. Additionally, the system may also provide a soft ferrite layer placed on the upper and lower pipe sections to enhance the magnetic coupling so that the wireless power transfer efficiency can be maintained at a sufficient level when the coil separation is relatively large. Notably, this ferrite layer may span most or the entirely of the region between the coils to further enhance performance. In some cases, a ferrite core may be position between the coils and the pipe as well. In some cases, the pipe may include a tool section that may be non-conductive or results in a discontinuity in the ferrite layer. However, the setup of the system allows power to be wirelessly transferred despite such discontinuity.

Abstract: Methods and systems for determining petrophysical parameters of a formation are provided. In one embodiment, a method includes acquiring formation data with a borehole imaging tool deployed in a well penetrating a formation and acquiring additional formation data with a dielectric logging tool deployed in the well. The method also includes calibrating the formation data acquired with the borehole imaging tool based on the additional formation data acquired with the dielectric logging tool. The calibrated formation data can then be used in determining a petrophysical parameter of the formation. Additional methods, systems, and devices are also disclosed.

Abstract: A resistivity logging tool includes a resistivity antenna and an antenna shield having a longitudinal slot segments interconnected to form an elongated slot with an elongated slot length that is longer than the length of the sleeve in which the slot segments are formed thereby enhancing electromagnetic wave strength propagated through the shield. Longitudinal slot segments may be interleaved to maximize the total number of elongated slots.

Abstract: A surface excitation ranging method includes selecting a first well with a metal casing as a target well and selecting a second well with a metal casing as a ground well. The method also includes installing a supplemental grounding arrangement for a power supply located at earth's surface, wherein the ground well and the supplemental grounding arrangement fulfill an impedance criteria or ranging performance criteria. The method also includes conveying an electrical current output from the power supply along the target well. The method also includes sensing electromagnetic (EM) fields emitted from the target well due to the electrical current. The method also includes using distance or direction information obtained from the sensed EM fields to guide drilling of a new well relative to the target well.

Abstract: A polyphase electric power supply system via which powerline communications are set up between a transmitter and a receiver. The transmitter: detects a first zero-crossing of an alternating electrical signal on a phase connected to the transmitter; determines a first instance when the transmitter is expected to transmit a dataset; determines a first time difference between the first zero-crossing and the first instance; includes in the data set information of the phase to which the transmitter is connected, when the first time difference is below a predefined threshold. The receiver: detects a second zero-crossing of the alternating electrical signal on the phase connected to the receiver; detects a second instant when the receiver receives the data set; determines a second time difference between the second zero-crossing and the second instant; determines the phase connected to the receiver, from the second time difference and the transmitter phase information.

Abstract: An example logging tool may include at least one transmitter antenna and at least one receiver antenna. A first high-impedance metamaterial may be disposed between the transmitter antenna and the receiver antenna. The first high-impedance metamaterial may include a periodic arrangement of patches, each of the patches being electrically coupled to a ground plane using a via.

Abstract: A rotary steerable bottom hole assembly includes a drill bit disposed at a distal end thereof, and azimuthal resistivity antennas and electronics configured to measure a distance to a formation boundary.

Abstract: A method for making gain compensated electromagnetic logging measurements of a subterranean formation includes rotating an electromagnetic logging tool in a subterranean wellbore. The logging tool includes a transmitter having at least one transmitting antenna axially spaced apart from a receiver having at least one receiving antenna. Electromagnetic waves are transmitted into the subterranean wellbore using the at least one transmitting antenna. Voltage measurements corresponding to the transmitted electromagnetic waves are received at the receiving antenna. The voltage measurements are processed to compute real and imaginary directional resistivity measurement quantities.

Abstract: Disclosed embodiments include systems and methods of correcting induction logging data for relative dip. Initial induction logging data is measured at a plurality of frequencies. One example embodiment includes displaying dip corrected data for a plurality of different relative dip angles, which may further be displayed with a qualitative indicator displayed over many depth samples for selecting or validating a correct relative dip angle. The data may be iteratively processed using an automated relative dip correction algorithm and analyzed by the user to obtain and apply the best relative dip correction angle to induction logging data. Once dip corrected, the induction logging data can be used with resistivity methodologies generally designed for instances where no dip is present in the formation under analysis.

Abstract: An electromagnetic energy source for emitting pulses of electromagnetic energy includes a sonde assembly having a first section axially aligned with, and spaced from, a second section. An energy storage capacitor of the sonde assembly includes an electrode mounted in each of the first section and the second section of the sonde assembly and operable to generate an electric field, and a capacitive charge storage medium mounted in each of the first section and the second section of the sonde assembly and surrounding each electrode. The sonde assembly further includes a fast-closing switch located between the electrodes of the first and second sections of the sonde assembly.

Abstract: A method for performing a formation physical action includes: transmitting a first time-domain transient electromagnetic (EM) signal into a borehole and the formation using a downhole EM wave propagation tool, the first EM signal having frequency domain components in a range of at least 1 MHz to 1 GHz; receiving a second time-domain transient EM signal due to the transmitting of the first EM signal, the second EM signal having frequency domain components in the range of at least 1 MHz to 1 GHz; calculating attenuation and phase shift S-parameters as a function of frequency using the first and second EM signals; assigning to the formation at least one of a resistivity value and a permittivity value of a reference that matches or is within a selected range of the attenuation and phase shift S-parameters; and performing the physical action using the at least one of the resistivity value and the permittivity value.

Abstract: Apparatus (57, 58) for determining permittivity in a downhole location comprises a sensor (57) including an elongate conducting line (62) supported on or adjacent a first side of a dielectric substrate (61). The sensor (57) also includes at least one conducting ground element (26, 27) that is spaced from the conducting line (62), the conducting line (62) being capable of juxtaposition to a downhole borehole wall (12). The apparatus further includes connected respectively to spaced locations along the conducting line at least two terminals (31, 32; 63, 64) of a vector network analyser (57b) that is capable of detecting one or more signal reflection characteristics whereby when the sensor (57) is juxtaposed to a borehole wall (12) the vector network analyser (57b) generates one or more signals that are processable to indicate the relative permittivity of rock (39) in which the borehole is formed.

Abstract: A communication system for use with a well tool can include an of outer toroid antenna. The outer toroid antenna can be positionable around an outer housing of the well tool. The communication system can also include an inner toroid antenna positionable within the outer housing of the well tool. The communication system can further include a switch coupled to the outer toroid antenna and the inner toroid antenna. The switch can be operable to enable or disable a wireless communication via the outer toroid antenna or the inner toroid antenna.

Abstract: Provided are systems and methods for mapping hydrocarbon reservoirs. Operations include disposing an electromagnetic (EM) transmitter and an EM receiver into first and second wellbores of first and second wells, respectively, penetrating a resistive layer of a subsurface formation bounded by first and second conductive layers. The EM transmitter and receiver each being disposed at depths proximate to intersections of the first and second wellbores and the resistive layer, respectively. The operations further including transmitting an EM signal between the EM transmitter and receiver via the resistive layer, determining transport properties associated with propagation of the EM signal from the EM transmitter to the EM receiver via the resistive layer, and determining the presence of an anomaly in at least one of the conductive layers based on the travel time.

Abstract: A cement head including a tubular body having a top end and a bottom end, and a borehole arranged through at least a portion of the tubular body; a cement plug arranged in the borehole and configured to exit the cement head upon releasing a retention device; and a spool assembly arranged on the tubular body, wherein the spool assembly comprises a drum rotatable about a central axis and a continuous cable having a first end and a second end, the first end being attached to the drum and the second end being attached to the cement plug, and wherein rotating the drum about the central axis results in spooling or unspooling the continuous cable about the drum.

Abstract: Provided are systems and methods for mapping hydrocarbon reservoirs. Operations include disposing an electromagnetic (EM) transmitter and an EM receiver into first and second wellbores of first and second wells, respectively, penetrating a resistive layer of a subsurface formation bounded by first and second conductive layers. The EM transmitter and receiver each being disposed at depths proximate to intersections of the first and second wellbores and the resistive layer, respectively. The operations further including transmitting an EM signal between the EM transmitter and receiver via the resistive layer, determining transport properties associated with propagation of the EM signal from the EM transmitter to the EM receiver via the resistive layer, and determining the presence of an anomaly in at least one of the conductive layers based on the travel time.

Abstract: A method includes deploying an electromagnetic (EM) defect detection tool in a downhole environment having a plurality of tubular strings with different diameters. The method also includes receiving raw measurements collected by the EM defect detection tool. The method also includes deconvolving the raw measurements with another input to obtain deconvolved raw measurements. The method also includes using the deconvolved raw measurements to determine a defect in at least one of the plurality of tubular strings. The method also includes performing, by a device, an operation in response to the determined defect.

Abstract: Systems, methods, and apparatuses to generate a formation model are described. In one aspect, a logging system includes a transmitter to produce an electromagnetic field in a borehole, a receiver in the borehole to detect a first field signal induced by the electromagnetic field at a first depth of investigation and a second field signal induced by the electromagnetic field at a second depth of investigation, and a modeling unit to perform a first one-dimensional inversion on the first field signal and a second one-dimensional inversion on the second field signal, build a two-dimensional model from the first one-dimensional inversion and the second one-dimensional inversion, and perform a two-dimensional inversion on the two-dimensional model to generate a two-dimensional formation model.

Abstract: Disclosed embodiments include apparatus, systems, and methods which operate to include monitoring an electromagnetic signal and/or gamma ray spectra count values to determine interception of a first well created by a drill string, with a well casing surrounding a second well. Interception can be determined when a reception antenna is used to receive the electromagnetic signal, by examining values associated with the magnitude of the signal. Interception can also be determined when a ratio of the gamma ray spectra count values have exceeded a first predetermined threshold, or when capture gamma energy indicated by the gamma ray spectra count values exceeds a second predetermined threshold. Additional apparatus, systems, and methods are disclosed.

Abstract: The shape and size of a borehole may be characterized downhole, using measurements of the borehole shape in conjunction with a catalog of shapes against which the measured shape is matched. A unique identifier for the measured borehole shape, and optionally a size parameter, may be transmitted to a surface facility, generally saving bandwidth compared with the transmission of the raw measured borehole-shape data. Alternatively or additionally, downhole measurements may be adjusted based on the measured shape.

Abstract: Apparatus is provided featuring a signal processing module configured to receive signaling containing information about detected acoustic emissions related to ore being mined from a block cave in a block caving process, including falling ore that creates unique acoustic signatures; and determine information about the ore being mined from the block cave in the block caving process, based at least partly on the signaling received. The signal processing module may receive the signaling from an array of acoustic sensors placed around the block cave, including where the array of acoustic sensors surrounds the block cave in both vertical and horizontal directions. The signal processing module may provide corresponding signaling containing corresponding information about the ore being mined from the block cave in the block caving process, including where the corresponding information includes information about a distribution and size of the ore being mined from the block cave in the block caving process.

Abstract: A downhole drilling tool has a deep-reading logging tool, a near-bit resistivity tool, and a gamma ray detector. Formation information logged using the deep-reading logging tool is used to build a preliminary stratigraphic model with a relatively low resolution. The preliminary stratigraphic model is further refined using data logged using the near-bit resistivity tool and/or the gamma ray detector to obtain a refined stratigraphic model with a higher resolution. The model is used to guide geosteering to achieve better well placement and trajectory control.

Abstract: Complementary metamaterial elements provide an effective permittivity and/or permeability for surface structures and/or waveguide structures. The complementary metamaterial resonant elements may include Babinet complements of “split ring resonator” (SRR) and “electric LC” (ELC) metamaterial elements. In some approaches, the complementary metamaterial elements are embedded in the bounding surfaces of planar waveguides, e.g. to implement waveguide based gradient index lenses for beam steering/focusing devices, antenna array feed structures, etc.

Abstract: Identifying the dielectric constant and/or the electrical resistivity of part of a geological formation may reveal useful characteristics of the geological formation. This disclosure provides methods, systems, and machine-readable media to determine dielectric constant or electrical resistivity, or both, using contraction mapping. Specifically, contraction mapping may be used with a function of wavenumber k to iteratively solve for values of dielectric constant and electrical resistivity until convergence is achieved. This may allow for convergence to a solution without computing partial derivatives and/or with fewer iterations than previous techniques.

Abstract: The invention relates to an apparatus comprising an electromechanical device, a control unit and a motion detector, wherein said electromechanical device is controllable by said control unit via a control signal, wherein said motion detector is configured such that said mechanical movement of said electromechanical device is determined and wherein said motion detector provides a motion detector signal. The invention also relates to a method for operating an electromechanical device. The technical problem of providing an apparatus with an electromechanical device, the reliability as well as the power consumption of which is improved, is solved in that the control unit is configured such that it can be influenced by the phase difference between the control signal and the motion detector signal.

Abstract: In accordance with presently disclosed embodiments, a system and method for determining a measurement for a pseudo receiver antenna with a different lateral position and a different azimuthal direction than at least two receiver antennas disposed on one or more wellbore tools is provided. The method involves transmitting an electromagnetic signal into a subterranean formation surrounding a borehole, and measuring one or more responses of the subterranean formation to the electromagnetic signal using at least two receiver antennas. The two receiver antennas are oriented in differing azimuthal directions relative to one or more tools to which the receiver are coupled, and arranged in a non-parallel angular orientation with respect to each other. The method then includes determining a response measured by a pseudo receiver antenna with a desired angular orientation and a desired azimuthal direction with respect to the one or more tools.

Abstract: Electromagnetic sensors which provide high coupling gain between the transmitter and receiver of a dielectric tool include a conductive pad having a cavity filled with dielectric filler, and an electrical conductor that provides electrical current to a conductive feeder placed inside the dielectric filler. During operation, current is fed to the conductive feeder to thereby produce an electric monopole that feeds electromagnetic power into the cavity, which then radiates out into the formation as electromagnetic signals. Because of the design of the electromagnetic sensors, the transmitter/receiver coupling gain and SNR are optimized over the entire range of the dielectric constant (i.e., 5??r?80).

Abstract: Improved algorithm for estimating anisotropic formation resistivity profile using a multi-component induction tool are disclosed. A method for estimating anisotropic formation resistivity profile of a formation comprises obtaining borehole corrected log data and determining at an azimuth angle of the formation. One or more formation bed boundaries are located and initial formation properties are calculated. One of a plurality of inversion windows is sequentially selected and a one-dimensional inversion of each of the sequentially selected one of the plurality of inversion windows is performed.