Abstract: A three-dimensional electrical resistivity tomography method and system belonging to the field of geological geophysical prospecting, the method including the steps of prospecting a region containing a geological anomaly with at least two prospecting modes respectively to acquire two-dimensional resistivity data of a corresponding detection plane; unifying coordinate systems of resistivity data points acquired in all prospecting modes, and extracting data points with the same coordinates; carrying out data fusion on extracted resistivity data at the same position by utilizing a principal component analysis method; and carrying out three-dimensional coordinate conversion on resistivity data acquired after fusion to form a three-dimensional model.

Abstract: According to an embodiment, there is provided a method for mitigating seawater intrusion in the ground where an aquifer having a seawater-fresh water interface is formed, the method including: installing an injection well at a point on an inland area, spaced apart from the sea by a predetermined distance, to a predetermined injection depth (d), the injection well having a predetermined screen height; injecting seawater into the aquifer by a predetermined quantity of injection through the injection well; and forming an upper seawater area around the injection well by the injection of the seawater, wherein the upper seawater area is an area that is filled with seawater in an upper portion of the aquifer.

Abstract: Provided are a method, apparatus and system for measuring a resistance parameter of a grounding system, and a monitoring network. The method comprises: inputting a driving current into a plurality of sections of a grounding system path (S602), wherein the grounding system path comprises at least a grounded apparatus, a grounding body, and a downlead connecting the grounded apparatus and the grounding body; measuring response voltages generated by the plurality of sections, and acquiring a response current flowing through the downlead (S604); and determining a resistance parameter of the grounding system path according to the driving current, the response voltages and the response current (S606).

Abstract: A method for a multichannel geophysical data acquisition system is provided in the field of electrical resistivity tomography. Individual and autonomous node operating systems are provided. Separate communication channels for upstream and downstream data transfer, high voltage transfer and synchronization signals are provided. A novel use of high voltage isolation barriers is also provided. A direct memory access data transfer process is provided.

Abstract: A method of multichannel acquisition and geophysical data is provided. Individual and autonomous node operating systems are provided. Separate communication channels for upstream and downstream data transfer, high voltage transfer and synchronization signals are provided. The method provides for an alternating waveform of injected current to maximize data precision and minimize soil ionization. Node type assignment interleaving is also provided to compress survey time. Self calibration of nodes is provided as is self addressing of a node array.

Abstract: The present disclosure relates to a welding quality detecting field, and specifically relates to a quality detection device. The quality detection device includes an integrated probe set, a driving module and a collecting module. The integrated probe set includes a plurality of integrated probe assemblies. The integrated probe assemblies are disposed in pairs and each integrated probe assembly includes a driving end and a collecting end. The driving end of one integrated probe assembly is matched with the driving end of another integrated probe assembly disposed in pairs with the one integrated probe assembly. The collecting end of one integrated probe assembly is matched with the collecting end of another integrated probe assembly disposed in pairs with the one integrated probe assembly.

Abstract: Methods and systems for building a calibration database. A method may comprise hanging a logging tool in air, determining a raw response from the logging tool, decoupling a Zxx component and a Zzz component from the raw response, creating a modeled component from the Zxx component and the Zzz component, calculating an offset from the modeled component, interpolating the offset, modeling a response from the logging tool with the offset, or entering the response into a database. A system may comprise a logging tool, a conveyance, and an information handling system. A calibration system may comprise a crane, a logging tool, and an information handling system.

Abstract: A method and apparatus for discriminating between electric field sources. In one embodiment, the apparatus comprises a mobile detection system comprising a sensor probe for remotely measuring an electric field generated by an electric field source in a patrolled area; and a processor, coupled to the sensor probe, for processing data received from the sensor probe to generate a first field strength and at least a second field strength for determining whether the electric field source is potentially hazardous.

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: A method for detecting clogging of a subsurface flow constructed wetland, including the steps of firstly emptying water in the subsurface flow constructed wetland, and then measuring the apparent resistivity of the subsurface flow constructed wetland bed after the water is emptied, wherein the water holding capacity of clogging sediments in the clogged region after emptying is strong, the apparent resistivity of this region is further measured to be lower than an unclogged region and the clogged region can thus be positioned and analyzed, the apparent resistivity of the region clogged more seriously is lower and the degree of clogging can thus be quantitatively analyzed.

Abstract: A detection apparatus and method arranged to detect defects within a flexible pipe at least partially surrounded by seawater. The detection apparatus comprises a seawater electrode, an impedance monitor and a processor. The seawater electrode is arranged to be in contact with seawater surrounding at least part of a flexible pipe. The impedance monitor is arranged to measure the impedance between a metallic structural component of the flexible pipe extending at least partially along the length of the flexible pipe and the seawater electrode in response to an electrical test signal applied to the seawater electrode. The processor is arranged to determine the distance from the seawater electrode to a pipe defect electrically connecting the metallic structural component to seawater using the measured impedance.

Abstract: A method for transmitting data from a downhole instrument to a surface location includes running the downhole instrument into a wellbore on a line. The downhole instrument and at least a portion of the line are positioned inside a drill string. The downhole instrument includes first and second sets of fingers that contact an inner surface of the drill string. The downhole instrument measures an effect occurring in the drill string. The effect is due to perturbations in the drill string during a drilling process.

Abstract: A tool having two current electrodes, three or more voltage electrodes, and a measurement device capable of making electrical measurements is provided, along with a sample. With electrical connectivity to the sample, one current electrode is disposed at one location on the sample while the other current electrode is disposed at another location on the sample, and the three or more voltage electrodes are disposed on the sample intermediate the two current electrodes. An electric current is passed through the sample. The measurement device is used to make a first set of electrical measurements that involve a first pair of voltage electrodes and to make a second set of electrical measurements that involve a second pair of voltage electrodes. The first set of electrical measurements is compared to the second set of electrical measurements. It is inferred whether the sample has heterogeneous electrical properties using the compared electrical measurements.

Abstract: A system for diagnosing integrity of an electrical conductor-carrying system can include an electrical conductor-carrying network having a number of electrical conductor-carrying devices mechanically coupled to each other, where at least a portion of the electrical conductor-carrying network is made of electrically conductive material. The system can also include a number of sensor modules coupled to the electrical conductor-carrying network. The system can further include a control unit communicably coupled to the sensor modules. The sensor modules can measure at least one impedance in the electrical conductor-carrying devices of the electrical conductor-carrying network.

Abstract: A system for locating water floods, in some embodiments, comprises: multiple non-reference electrodes with insulative pads for coupling to a borehole casing; a reference electrode with an insulative pad for coupling to the borehole casing; and multiple transducers coupled to the reference and non-reference electrodes, each of said electrodes coupled to one or more of the multiple transducers, wherein each transducer coupled to a non-reference electrode determines a differential non-reference potential between that non-reference electrode and the reference electrode, and wherein a transducer that couples to the borehole casing determines an absolute reference potential between the borehole casing and the reference electrode; wherein the differential non-reference potentials are mathematically combined with the absolute reference potential to produce absolute non-reference potentials; wherein scaling weights are applied to said absolute non-reference potentials to produce scaled absolute potentials that are use

Abstract: The present invention relates to acoustic wavefields produced using sources appropriately delayed in time and focused at known positions and times in a heterogeneous medium. Seismoelectric conversion occurs if the acoustic focus point coincides with a discontinuity in electrical and hydrological medium properties, thus generating a current density. The current generates a potential difference, which can be observed at a distance by an array of monitoring electrodes. Since the acoustic wavefield is precisely located at a position and time, this electrical source behaves like a controlled virtual electrode whose properties depend on the strength of the acoustic wavefield and on the medium properties. This procedure can be used to increase the robustness and resolutions of electrical resistivity tomography and to identify hydrological parameters at various points in the medium by scanning the medium by changing the position of the acoustic focus.

Abstract: A resistivity logging system includes a plurality of excitation electrodes, at least one return electrode, and a plurality of monitor electrodes. The resistivity logging system also includes a controller that determines a level of excitation current to be emitted by at least one of the plurality of excitation electrodes during a subsequent excitation cycle based on a comparison of measured downhole parameter values corresponding to excitation current emitted in two previous excitation cycles.

Abstract: The invention discloses three-dimensional focusing induced polarization equipment for advance geological prediction of a water inrush disaster source in underground engineering, comprising a constant-current multiplex transmitter, an intelligent multichannel receiver, an automatic multi-electrode switch, an industrial personal computer, an observation electrode array and shielding electrodes, wherein electrodes in the observation electrode array are respectively used as a source electrode and observation electrodes; the industrial personal computer controls the constant-current multiplex transmitter to transmit currents of the same polarity to the shielding electrodes and the source electrode, so that the currents of the source electrodes are nearly directed straight ahead of a driving face under the action of the shielding electrodes; the observation electrodes are used for scanning data acquisition, and the data are fed back to the industrial personal computer through the intelligent multi-channel receiver;

Abstract: A method for detecting a time synchronization ability of the real-time measuring device based on a time variable is provided. On a premise that the real-time measuring device correctly receives time service signals, the method aims at detecting time synchronization signal application ability of the real-time measuring device, and involves a purely resistive loop comprising a value transferring device and a time controllable switch. The method, via a time synchronization performance thereof, relatively completely reflects the time synchronization signal application ability of the device within a value transfer requirement. The method is a development upon power station time synchronization time service signals and transmission accuracy detection and an improvement of power station time synchronization detection procedures. The method facilitates improving real-time analysis and monitoring abilities of a power station and a power grid to a primary device and a primary system.

Abstract: In a calibration process, a capacitor unit is removed from end terminals, or namely, respective capacitors are not connected to terminals. A prescribed voltage (a known voltage) is applied between these end terminals. Among bypass switches of a bypass circuit, the bypass switches connected to one terminal or two or more consecutive terminal pairs from the positive end terminal side are ON. Terminal voltages other than the negative end terminal are obtained and stored as calibration information.

Abstract: The present disclosure describes various geophysical survey systems and methods for mapping an electric potential field. At least one illustrative embodiment includes an electromagnetic (EM) source and geophysical survey cables that each includes multiple electrodes spaced apart along each geophysical survey cable's length, and multiple data acquisition units that each obtains measurements indicative of an electric potential between two the electrodes. A modeling module is included and configured to calculate a reference potential at a selected electrode for each of the plurality of geophysical survey cables, as well as a calculation module to combine signals representative of the measurements to produce signals indicative of the electric potential of each electrode relative to the reference potential.

Abstract: A method of testing the electric field recording of a marine electromagnetic sensor cable including electrodes is provided. The method includes causing time varying current to flow between at least one pair of current electrodes disposed along the marine electromagnetic sensor cable. The flow of current generates a voltage in a body of water, thereby causing a secondary field impressed on a pair of sensor electrodes disposed along the marine electromagnetic sensor cable. A potential difference between the pair of sensor electrodes is measured. Accuracy of the electric field recording is inferred from the measured potential difference.

Abstract: Disclosed are methods and systems for marine geophysical surveying that include a combined electromagnetic source electrode and deflector. An example embodiment discloses an electromagnetic source assembly comprising: a deflector-source electrode, wherein the deflector-source electrode comprises an electromagnetic source electrode integrated into a deflector; a separate electromagnetic source electrode; and a power source coupled to the electromagnetic source electrode and the separate electromagnetic source electrode.

Abstract: The present disclosure describes various geophysical survey systems and methods for mapping an electric potential field. At least one illustrative embodiment includes an electromagnetic (EM) source and geophysical survey cables that each includes multiple electrodes spaced apart along each geophysical survey cable's length, and multiple data acquisition units that each obtains measurements indicative of an electric potential between two the electrodes. A calculation module is included and configured to combine signals representative of the measurements to produce signals indicative of the electric potential of each electrode relative to a reference potential assumed to be present at a selected electrode for each of the plurality of geophysical survey cables. Each reference potential is assumed to be of a magnitude that is within a tolerance range of a common reference potential.

Abstract: Method for assessing hydrocarbon source rock potential of a subsurface region without well log information. The method uses surface electromagnetic (121) and seismic (122) survey data to obtain vertical profiles of resistivity and velocity (123), which are then analyzed in the same way as well log data are analyzed by the well known Delta Log R method (124).

Abstract: Controlling electromagnetic (‘EM’) radiation in a data center having a number EM sections, including: receiving, by an EM controller, a specification of preferred EM radiation characteristics for the data center; and setting, by the EM controller, a state of each EM section in accordance with the specification, where the state of each EM section may be one of: an absorption state in which the EM section absorbs EM radiation or a reflection state in which the EM section reflects EM radiation.

Abstract: Controlling electromagnetic (‘EM’) radiation in a data center having a number EM sections, including: receiving, by an EM controller, a specification of preferred EM radiation characteristics for the data center; and setting, by the EM controller, a state of each EM section in accordance with the specification, where the state of each EM section may be one of: an absorption state in which the EM section absorbs EM radiation or a reflection state in which the EM section reflects EM radiation.

Abstract: The present disclosure relates to methods and systems for detecting electric potential difference in water. A first electrode comprising a first electrode body is configured to be in electrical contact with the water when the device is disposed in the water. A second electrode comprising a second electrode body is configured to be in electrical contact with the water when the device is disposed in the water. An electrical connection exists amongst the first electrode, the second electrode, and a voltage measuring device. At least one of the first electrode body and the second electrode body is formed at least partially of a carbon aerogel material.

Abstract: The present disclosure relates to determining a property, such as resistivity, of an earth formation. A transmitter is disposed in a wellbore penetrating the formation, and a plurality of receivers are distributed on or near the earth's surface. The transmitter sends electromagnetic energy into the formation and the resulting signal, after passing through the formation, is detected by the array of receivers. The received signal is used to determine the property of the formation. This is often achieved using an inversion or numerical model of the formation being measured. The inversion takes into account changes in the background formation model due to transmitting from various locations. The measurements made on the formation can be performed while drilling the wellbore or subsequent to the drilling.

Abstract: An apparatus for making a resistivity measurement of an underground formation surrounding a borehole is provided. The apparatus includes a conductive tool body, at least one current injector electrode positioned between the tool body and a wall of the bore hole, at least one current return electrode positioned between the tool body and the wall of the bore hole, an electrical measurement device configured to monitor a voltage or a current signal indicative of an impedance imbalance, a regulator connected to the electrical measurement device, whereby the regulator is configured to receive the voltage or the current signal indicative of the impedance imbalance and is configured to generate an adjustment signal based on the voltage or the current signal indicative of the impedance imbalance.

Abstract: Disclosed is an apparatus for estimating a property of an earth formation penetrated by a borehole having a substantially non-conducting liquid. The apparatus includes: a downhole tool having a transmitter electrode configured to convey an electric current into the earth formation. A measurement electrode is configured to receive the electric current from the earth formation, wherein the electric current bridges as least one of a first gap between the transmitter electrode and the formation and a second gap between the measurement electrode and the formation. A compensating circuit coupling the transmitter electrode to the measurement electrode is configured to reduce a reactive component of a total current received by the measurement electrode. A receiver coupled to the measurement electrode is configured to measure the total current to estimate the property.

Abstract: A method of monitoring an extent of a hydrocarbon reservoir (2) below the earth's surface (4), includes the steps of applying a current between a bottom current electrode (6) and a top current electrode (8) that is part of a plurality of electrodes that are spaced apart from one another along a part of the earth's surface located above and optionally over the hydrocarbon reservoir. The bottom current electrode is positioned below the hydrocarbon reservoir. The method includes the step of measuring an electrical potential, which is caused by the current, by means of a measurement electrode (10A) that is also part of the plurality of electrodes. The method includes the step of inferring from the measured electrical potential the extent of the hydrocarbon reservoir, in a direction that is oriented substantially parallel with the earth's surface.

Abstract: A method and apparatus of constructing a signal for a controlled source electromagnetic survey is described. In one embodiment, a method is described that includes determining a first waveform and a second waveform, the first waveform and second waveform related to a combined frequency spectrum and bandwidth associated with a geophysical survey line. Then, a signal is constructed by sequencing the first waveform with the second waveform. This signal may be utilized in a transmitter, which may be pulled by a vessel along the geophysical survey line.

Abstract: A marine electromagnetic receiver cable includes a plurality of signal processing modules disposed at spaced apart locations along the receiver cable. A power supply line is connected to each of the signal processing modules and to an electric current source. A current regulation device is connected in the power supply line proximate each signal processing module. The current regulation devices are connected such that an amount of current flowing through the power supply line is substantially constant. At least one electromagnetic receiver is functionally coupled to an input of each signal processing module.

Abstract: Method of determining electrical anisotropy in a subsurface formation, wherein electromagnetic field data from a multi-offset electromagnetic survey obtained by using an electromagnetic source and a plurality of electromagnetic receivers at varying offset distances from the source is provided. The electromagnetic field data comprises a first set of multi-offset response signals received at each receiver with the electromagnetic source emitting at a first frequency, and at least one additional set of multi-offset response signals received at each receiver with the electromagnetic source emitting at a different frequency. The presence of electrical anisotropy in the subsurface formation is determined using the first and at least one additional sets of multi-offset response signals.

Abstract: An apparatus for determining a type of an electromagnetic wave generating source, including: a measurement unit that measures electromagnetic field strength at first and second measurement points at vertically different respective distances from a main surface of an object to be measured; a calculation unit that calculates an attenuation amount of the electromagnetic field strength between the first and second measurement points using measured values of the electromagnetic field strength measured by the measurement unit; and a determination unit that determines whether the generating source is the electric current source or the magnetic current source by judging which one of a reference value of an electric current source and a reference value of a magnetic current source is close to a value of the attenuation amount calculated by the calculation unit.

Abstract: An electromagnetic sensor cable has components including a first sensor cable segment having a plurality of spaced apart electrodes on the first sensor cable segment an electrical conductors coupled to the electrodes such that at least one of the electrodes is electrically connectible at at least one longitudinal end of the first sensor cable segment. The sensor cable includes a second sensor cable segment configured substantially the same as the first sensor cable segment. A first signal processing and configuration module has signal processing circuitry configured to perform at least one of measuring voltages across selected pairs of electrodes, and communicating signals representative of voltages measured across selected pairs of electrodes. The cable components are each configured to connect at the lateral ends one to another.

Abstract: An apparatus, method and computer-readable medium for obtaining a resistivity image of an earth formation. The apparatus includes a downhole assembly configured to be conveyed in a borehole penetrating the earth formation; a plurality of sensor electrodes on the downhole assembly, at least one of the electrodes having a different area than another of the electrodes; and at least one processor configured to: (i) process measurements using each of the sensor electrodes; (ii) process a subset of the measurements substantially unaffected by the different capacitances to produce an image of the borehole wall; and (iii) record the image on a suitable medium.

Abstract: A system for measuring a resistivity parameter of an earth formation includes: at least one measurement electrode electrically connected to a first electrical source; at least one guard electrode; a shielding electrode interposed between the at least one guard electrode and the at least one measurement electrode, the shielding electrode being electrically connected to a second electrical source independent from the first electrical source, and the guard electrode being electrically connected to a third electrical source independent of the first and second electrical sources; at least one return electrode; insulators positioned between (i) the measurement electrode and the shielding electrode, (ii) the shielding electrode and the guard electrode and (iii) the measurement electrode, the guard electrode and the return electrode; and a processor configured to adjust at least one of the first electrical source and the second electrical source to minimize a current flow through the shielding electrode.

Abstract: A method for measuring resistivity variations in the earth comprising passing a transient current between two source electrodes; measuring the transient current at the source electrodes; measuring the resultant transient voltage between at least one pair of receiver electrodes; estimating one or more processing functions for applying to the measured input current to provide a step current profile, and applying the same one or more processing functions to the measured voltage to provide an estimate of the step response voltage between the receivers, using both the step current and the estimated step response voltage to determine the resulting apparent earth resistance, and using the apparent earth resistance to determine the resistivity of the earth.

Abstract: A device and method for measuring electromagnetic signals that can be used to take measurements at or near the sea floor. The device comprises a central housing, a data management system located within the housing and at least two arms extending outwards from the housing. Each arm comprises a flexible elongate sheath attached to the housing, a sensor head, a flexible electrical cable attached to the sheath and connecting the sensor head to the data management system and a rod which is removeably locatable within the sheath. The rod is connectable relative to the housing at one end and connectable relative to the sensor head at the end remote from the housing.

Abstract: A method of testing the electric field recording of a marine electromagnetic sensor cable including electrodes is provided. The method includes causing current to flow between a pair of first electrodes disposed along the marine electromagnetic sensor cable. The flow of current generates a voltage that is impressed on a pair of second electrodes disposed along the marine electromagnetic sensor cable. A potential difference between the pair of second electrodes is measured. Accuracy of the electric field recording is inferred from the measured potential difference.

Abstract: A method of estimating a property of an earth formation penetrated by a borehole includes: disposing into the borehole a sensor having a plurality of return electrodes and at least one transmitter electrode disposed in a concentric arrangement; injecting a first current of a first frequency into the formation by applying an alternating current voltage between first selected ones of the plurality of return electrodes and the at least one transmitter electrode; injecting a second current of a second frequency into the formation by applying an alternating current voltage between second selected ones of the plurality of return electrodes and the at least one transmitter electrode; measuring effective impedance for each of the currents; and estimating the property using the measurements of the effective impedance for each of the currents; wherein the estimating compensates for an influence of standoff distances of the sensor on the measurements.

Abstract: To perform marine electromagnetic (EM) surveying of a subterranean structure, a marine cable system is provided including a tow cable, a plurality of electromagnetic (EM) sources coupled to the tow cable, and a plurality of EM receivers coupled to the tow cable. The system is configured for deployment in a body of water to perform marine EM surveying of a subterranean structure.

Abstract: A method for survey of hydrocarbon deposits in a researched profile of sea-bottom comprises providing a generator generating pulse electric current with a generator frequency in a towable generator line exciting electric field signals measured by sea-bottom stations synchronized with the generator, forming space-domain data arrays for the generator frequency and for higher odd harmonics frequencies nearest thereto, forming time-domain data arrays for selected offsets, inversion of the time-domain and space-domain data, and determining a bottom strata resistivity and polarization characteristics for the researched profile, based the inversion's results. The inversion preferably encompasses synchronizing and adjusting the generator line and electric field signals, dividing them into a frequency branch, including a fast Fourier transform and a robust summation producing the space-domain arrays, and a time-domain branch, including a robust summation producing the time-domain arrays.

Abstract: To perform an electromagnetic (EM) surveying of a subterranean structure, a signal generator produces a signal having an analog continuous waveform without steps in the waveform. Producing the signal is in response to an indication specifying a characteristic of the signal. An antenna is responsive to the signal having the analog continuous waveform to emit an EM field to produce the EM surveying of the subterranean structure.

Abstract: A method and apparatus of constructing a signal for a controlled source electromagnetic survey is described. In one embodiment, a method is described that includes determining a first waveform and a second waveform, the first waveform and second waveform related to a combined frequency spectrum and bandwidth associated with a geophysical survey line. Then, a signal is constructed by sequencing the first waveform with the second waveform. This signal may be utilized in a transmitter, which may be pulled by a vessel along the geophysical survey line.

Abstract: A method for analyzing acquired electromagnetic measurements (R) made at or in a sea (4) over a seafloor (1) with rock formations (3) having relatively low resistivity (?3) for detecting a possibly underlying petroleum bearing reservoir formation (2) having relatively high resistivity (?2), wherein a low frequency electromagnetic transmitter (5) arranged in the sea (4) emits an electromagnetic field (P) propagating in the sea (4), in the rocks (3, 2) and in the air (0) above the sea; wherein electromagnetic sensors (6) are arranged with desired offsets (x) in the sea (4) for measuring the electromagnetic field (P(x)) while the field propagates, characterized in that one or more component of the electromagnetic field (P) is measured at least one large offset (xL) from the transmitter (5) where the field (P) essentially only has its origin from the field propagating as a field (P0) through the air (0); that the one or more components of the electromagnetic field (P) measured at the large offset (xL) is calculat

Abstract: A method for measuring a resistivity parameter of an earth formation is provided. The method includes: conveying a measurement current from at least one measurement electrode into the formation, the at least one measurement electrode having a potential; receiving the measurement current by at least one return electrode; and estimating a resistivity parameter from a measurement value selected from at least one of the measurement current and the potential, the resistivity parameter based on (i) an impedance calculated from the measurement value and (ii) a correction factor calculated from a plurality of measurement values related to a conductivity of a fluid in a borehole and a dielectric constant of the fluid in the borehole. A system for measuring a resistivity parameter of an earth formation is also provided.

Abstract: A target is sensed by an antenna array having a transmitter antenna and a receiver antenna, both of which are caused to be electromagnetically coupled to the target. The antenna array is rotated, and as the array rotates, a change in at least one of the coupling between the transmitter antenna and the target and the coupling between the receiver antenna and the target is detected at multiple rotational orientations of the antenna array.