Abstract: The subject disclosure relates to techniques for correcting logging depth of a well bore. A process of the disclosed technology can include receiving a first sensor measurement from a first sensor disposed in a wellbore, receiving a second sensor measurement from a second sensor disposed in the wellbore, wherein the first sensor and the second sensor are disposed on a wireline with a predetermined distance between the first sensor and the second sensor, generating a correlation function based on the first sensor measurement and the second measurement, and determining, based on the correlation function, whether the measurements indicate a perceived distance between the first sensor and the second sensor deviating from the predetermined distance.

Abstract: A magnetism detection apparatus includes a detection device, at least one first locating device, and a central control device. The detection device includes an array of detection assemblies arranged in a same plane. The array of detection assemblies is configured to detect magnetic fields and output magnetic field signals corresponding to locations of the detection assemblies. The at least one first locating device is disposed on one of the detection assemblies to locate this detection assembly and output a first coordinate signal corresponding to this detection assembly. The central control device is communicatively and respectively connected to each of the detection assemblies and the at least one first locating device, and configured to process the magnetic field signals and the first coordinate signal.

Abstract: A detection method for discovering an unexploded ordnance includes: surrounding a detection region with a transmitting coil and surrounding a detection site with a second receiving coil; conducting the transmitting coil with a second electric current; respectively acquiring a plurality of second feedback signals at a plurality of second feedback time points; partitioning the transmitting coil into a plurality of dipoles, and acquiring a plurality of distance values r respectively between the plurality of dipoles and the detection site; respectively calculating feedback depths according to feedback time periods; respectively calculating apparent resistivity values corresponding to the feedback depths; obtaining an apparent resistivity distribution in depth at the detection site according to the apparent resistivity values and the feedback depths; and judging whether there is any unexploded ordnance at the detection site according to the apparent resistivity distribution in depth.

Abstract: Methods, systems, and apparatus, including computer programs encoded on a computer storage medium, for detecting seepage of hydrocarbons in subterranean zones. In one aspect, a method includes detecting hydrocarbon seepage at multiple different sampling depths from a surface in a surveyed geographic region, comparing each of the hydrocarbon seepage at the multiple different sampling depths, wherein hydrocarbon seepage at a reference depth is known, and determining hydrocarbon seepage through the surveyed geographic region based on a result of the comparison.

Abstract: An exemplary inventive optimization model delineates a three-dimensional geometric environment for situation therein of electromagnetic sources and an electromagnetic sensor array used for measuring electric and magnetic fields emanating from the electromagnetic sources. Based on measurements and computations relating to electrical, magnetic, and structural physical properties, the geometric environment is stratified into air, sea, and seafloor regions as well as into electromagnetically distinct zones. The design of the electromagnetic sensor array is optimized through an iterative process involving successive determinations as to how well the electric and magnetic fields emanating from the electromagnetic sources may be calculated based on measurements taken in the geometric environment by the electromagnetic sensor array. Every instance of the electromagnetic sensor array in the iterative process is uniquely located and/or uniquely configured vis-à-vis every other instance.

Abstract: The present disclosure relates to a magnetic-sensor device comprising a circuit board made of an electrically insulating material and having conductor tracks, and comprising a permanent magnet surface-mounted on the circuit board, and a magnetic-field sensor connected to the conductor tracks of the circuit board. An SMD component for populating a circuit board is also proposed, which SMD component comprises a permanent magnet and a magnetic-field sensor.

Abstract: Disclosed is a method for analyzing a blind zone of a magnetic detection method that can provide a complete distribution map of the detection blind zone within the entire zone of the magnetic target. The method comprises the first step of establishing a complete magnetic detection model to obtain calculated position and magnetic moment of a magnetic target that is detected by a magnetic gradiometer. The second step involves establishing a direction-attitude-sphere model to represent the entire zone of the magnetic target. The third step involves expanding the direction-attitude-sphere to a planar map layered by latitude and calculating success detection rates within the planar expansion map. Finally, the distribution map of the magnetic detection blind zone in the entire zone is visually presented in the planar expansion map and a complete distribution rule of the entire detection blind zone is thus obtained.

Abstract: Provided is a method for designing a magnetic gradiometer based on the combined influence of multiple influencing parameters. The method takes into consideration of synergetic interaction of the influencing parameters on the performance of a magnetic gradiometer. It analyzes detection errors within the entire zone of all possible directions and attitudes of a magnetic target under the influence of various influencing parameters, uses the detection accuracy and detection success rate to measure the performance of the magnetic gradiometer accurately and objectively, and finally obtains the influence rule of the influencing parameters on the performance of the magnetic gradiometer. Based on the knowledge of the combined influence of multiple influencing parameters, the magnetic gradiometer can be designed to have high detection accuracy and success rate and high cost-efficiency.

Abstract: A display device includes a first substrate including a display area and a non-display area, pixels disposed in the display area, a driver integrated circuit located in the non-display area and connected to the pixels through data lines, a first pad portion disposed in the non-display area, a second pad portion disposed in the non-display area and connected to the driver integrated circuit, a first thin film transistor connected to one of the data lines and adjusting a first data signal, a second thin film transistor connected to another of the data lines and adjusting the first data signal, a first wiring connecting the first thin film transistor and the first pad portion, a second wiring connecting the second thin film transistor and the second pad portion, and a gate signal line connected to the first and second thin film transistors.

Abstract: A method of operating a capacitive sensing device for diagnosing a galvanic connection of at least one guard electrode. The capacitive sensing device includes at least one sense-guard capacitive sensor and a capacitive measurement circuit. The sense-guard capacitive sensor includes a first electrically conductive sense electrode and a first electrically conductive guard electrode and at least a second electrically conductive sense electrode, which is galvanically separated from the first sense electrode, and at least a second electrically conductive guard electrode. Each of the guard electrodes is proximally arranged to at least one of the sense electrodes and is galvanically separated from each of the sense electrodes. The method uses a calculated difference of imaginary parts of complex sense currents resulting from coupling mode measurements between at least two of the sense electrodes for assessing a status of the galvanic connection of the guard electrodes.

Abstract: An amphibious portable magnetism detector includes a first housing, a first wiring tube, a first magnetic field sensor, and a central control device. The first housing defines a first inner space and a first through hole in communication with the first inner space. The first wiring tube is connected to the first housing with a first leak-tight seal formed between them, and in communication with the first inner space via the first through hole. The first magnetic field sensor is disposed in the first inner space and configured to detect a magnetic field at a target area and generate a first detection signal. The central control device is electrically connected to the first magnetic field sensor and configured to receive the first detection signal and output a first magnetic field value according to the first detection signal.

Abstract: Disclosed are a method and system of magnetotelluric synchronous detection and real-time inversion. The system includes a detection and inversion host (M) with wireless networking function and N2-1 detection and inversion extensions (Si) with wireless communication functions. The distance between each two detection and inversion extensions (Si) is D, i=1, 2, . . . , N2-1, and N is an odd number. The detection and inversion host is configured for collecting magnetic field signals and electric field signals at measurement points, wireless networking and cooperation, synchronous detection and real-time inversion control of the detection and inversion extensions (Si) in detection area. The detection and inversion extensions (Si) are configured for synchronous collection of electric field signals at measurement points and real-time inversion of detection data at measurement points under cooperative control of the detection and inversion host.

Abstract: A method for locating a buried casing stub may comprise a) identifying a target region, b) providing at each of a plurality of survey points in the target region a casing stub locator that includes a vector magnetometer, c) measuring the magnetic field at each of the survey points using the vector magnetometer so as to generate a plurality of magnetic field measurements, d) using the magnetic field measurements to generate a model of the magnetic field of the target region, e) fitting the model generated in step d) to a selected model of a magnetic anomaly created by the casing stub so as to generate model fit information (MFI), and f) locating the casing stub using the MFI. At each survey point, an expected Earth magnetic field can be subtracted from the measured magnetic field. A total station can measure the position and/or the azimuth of the package.

Abstract: A metallic foreign object detector is used in a wireless power transmission system that transmits power by wireless from a feeding coil to a receiving coil and includes an antenna coil, a capacitor that forms a resonance circuit together with the antenna coil, a vibration detection circuit configured to detect generation of a vibration signal in the resonance circuit, and a determination circuit that detects the presence/absence of a metallic foreign object according to the vibration signal. The vibration detection circuit is configured to output a detection state signal indicating the detection state of generation of the vibration signal. The determination circuit is configured to execute an operation of detecting the presence/absence of a metallic foreign object according to the detection state signal.

Abstract: A method for determining tubing permeability includes conveying a tool through a tubular string in a borehole. The tool includes a transmitter that transmits a primary electromagnetic field and a receiver that receives at least one collar response. The collar response includes a secondary electromagnetic field produced in response to the primary field by a collar in the tubular string. The method further includes determining a permeability of at least one portion of the tubular string based on a magnitude of the at least one collar response. The method further includes displaying a representation of the at least one portion of the tubular string based on the permeability.

Abstract: Methods, systems, and apparatus, including computer programs encoded on a computer storage medium, for detecting seepage of hydrocarbons in subterranean zones. In one aspect, a method includes detecting hydrocarbon seepage at multiple different sampling depths from a surface in a surveyed geographic region, comparing each of the hydrocarbon seepage at the multiple different sampling depths, wherein hydrocarbon seepage at a reference depth is known, and determining hydrocarbon seepage through the surveyed geographic region based on a result of the comparison.

Abstract: Methods, systems, and apparatus, including computer programs encoded on a computer storage medium, for detecting seepage of hydrocarbons in subterranean zones. In one aspect, a method includes detecting hydrocarbon seepage at multiple different sampling depths from a surface in a surveyed geographic region, comparing each of the hydrocarbon seepage at the multiple different sampling depths, wherein hydrocarbon seepage at a reference depth is known, and determining hydrocarbon seepage through the surveyed geographic region based on a result of the comparison.

Abstract: A ball detection and tracking system including one or more visual sensors and a detection and tracking agent that ranks a plurality of blob detection algorithms based on a detection metric and uses a selected base detection algorithm to identify one or more candidate blobs. Based on this, the agent is able to generate a track for the candidate blobs and assign one or more subsequent candidate blobs to a best ranked one of the tracks if the assignment satisfies a cost threshold.

Abstract: Methods, systems, and apparatus, including computer programs encoded on a computer storage medium, for detecting seepage of hydrocarbons in subterranean zones. In one aspect, a method includes detecting hydrocarbon seepage at multiple different sampling depths from a surface in a surveyed geographic region, comparing each of the hydrocarbon seepage at the multiple different sampling depths, wherein hydrocarbon seepage at a reference depth is known, and determining hydrocarbon seepage through the surveyed geographic region based on a result of the comparison.

Abstract: The invention discloses an air-ground integrated geomagnetic field combined observation method and system. The method comprises the following steps of validating local geomagnetic field model parameters using the geomagnetic field data collected by a mobile earth station before the geomagnetic field survey mission is executed; getting a dynamic model along the flight path using the geomagnetic field data collected by the airborne console over the flight path and the model parameters when the geomagnetic field survey mission is executed; getting a measuring error model along the flight path using the attitude measuring error obtained by the airborne console when the aircraft flies as per the preset attitude; getting the estimation of the geomagnetic field data collected over the flight path in a geographic coordinate frame using the dynamic model and the measuring error model.

Abstract: A device and method for calculating electrical properties of a surveyed underground formation. The method includes selecting a waveform having multiple current transition rates; placing a time-domain electromagnetic (TEM) system above the underground formation while generating with a transmitter a transient primary magnetic field during an on-time period and no magnetic field during a following off-time period, due to the waveform; and recording with a receiver magnetic related data generated by the earth as a result of the transient primary magnetic field. The receiver records the magnetic related data during the on-time period using plural on-time gates sampling.

Abstract: Methods, systems, and apparatus, including computer programs encoded on a computer storage medium, for detecting seepage of hydrocarbons in subterranean zones. In one aspect, a method includes detecting hydrocarbon seepage at multiple different sampling depths from a surface in a surveyed geographic region, comparing each of the hydrocarbon seepage at the multiple different sampling depths, wherein hydrocarbon seepage at a reference depth is known, and determining hydrocarbon seepage through the surveyed geographic region based on a result of the comparison.

Abstract: An electronic device may include a device housing, a haptic actuator carried by the device housing, and an audio input transducer carried by the device housing. The electronic device may also include a controller coupled to the audio input transducer and the haptic actuator. The controller may be capable of determining a sound level of the haptic actuator, attempting to drive the haptic actuator to operate within a desired sound level range, and when unable to drive the haptic actuator within the desired sound level range, then generating a warning indication.

Abstract: A system for optimizing placement of a second wellbore relative to a first wellbore utilizing i) steam injected into the first wellbore in combination with a temperature sensor located in the second wellbore and ii) electromagnetic (EM) fields emanating from the first wellbore in combination with an EM sensor in the second wellbore. The magnetic measurements made with the EM sensor are utilized to determine azimuthal placement of a wellbore, while temperature measurements made with the temperature sensor are utilized to determine distance for placement of the wellbore.

Abstract: An electronic device may include a device housing, a haptic actuator carried by the device housing, and an audio input transducer carried by the device housing. The electronic device may also include a controller coupled to the audio input transducer and the haptic actuator. The controller may be capable of determining a sound level of the haptic actuator, attempting to drive the haptic actuator to operate within a desired sound level range, and when unable to drive the haptic actuator within the desired sound level range, then generating a warning indication.

Abstract: Resistivity in subsurface earth at locations kilometers away from wells in the reservoirs is mapped and monitored. An electromagnetic source with an electrode is deployed a borehole in the reservoir, and a group of sensors at counter electrodes is deployed at a number of other locations radially spaced at some distance from the well. The source transmits a current which flows to the counter electrodes causing an electromagnetic field which is sensed at the sensors. The source is activated at different depths in the well and ratios of the electromagnetic field sensed with the source at different depths used to obtain data to map the resistivity. The sensors are capable of sensing electromagnetic fields along two orthogonal axes, and the measurements at a sensor along these axes used to reduce undesirable effects of noise and other factors on the data measurements.

Abstract: Buried object locator systems including transmitters and associated buried object locators using phase-synchronized signals are disclosed. A transmitter may generate output current signals that are phase-synchronized such that an associated locator may receive magnetic field signals from the output current signal and determine information about the current flow based on independent phase-synchronization timing information.

Abstract: In seismic survey for icy waters, streamers are towed behind a vessel under the water's surface to avoid ice. GPS readings may not be consistently obtained because the ice prevents a tail buoy with a GPS receiver from trailing from streamer at the surface. Instead, a device tows on the streamer under the water's surface. The streamer's absolute position is tracked by intermittently bringing the towed device toward the surface so GPS readings can be obtained. The streamer's absolute position can then be used in conjunction with compass readings and can correlate various seismic sensor signals obtained along the streamer during the survey. The compass readings can be corrected for declination using declinometer readings, which can be compensated for iron effects from the vessel or other device carrying the declinometer.

Abstract: Methods for rapidly determining earthquake parameters of an earthquake include inputting a seismogram of the earthquake, searching concurrently in pre-established historical seismogram database and theoretical seismogram database by use of an approximate nearest neighbor search method, to find a set of seismograms similar to the input seismogram according to a preset similarity condition, and determining from the set of similar seismograms one or more seismograms matched with the input seismogram, and determining the earthquake parameters from the matched seismograms. With the present invention, it is possible to search in millions of seismograms and determine parameters for an earthquake in a few second, and thus realize rapid and even real-time estimation of earthquake parameters.

Abstract: A magnetic field generating device includes a triaxial Helmholtz coil 3, amounting table 4 on which a portable device 2 is mounted, a current supplying part 5 and a controlling part 6. The current supplying part 5 supplies current I to individual three monoaxial Helmholtz coils 30 which construct the triaxial Helmholtz coil 3. The controlling part 6 changes the current flowing through the individual monoaxial Helmholtz coils 30 in such a manner that a synthetic magnetic field of a magnetic field generated within the triaxial Helmholtz coil 3 by the current I and an external magnetic field which acts from the outside into the triaxial Helmholtz coil 3 acts on a triaxial magnetic sensor 20 within the portable device 2 mounted on the mounting table 4 from a plurality of predetermined directions.

Abstract: The present disclosure relates to systems and methods for conducting an electromagnetic borehole-to-surface survey of a formation surrounding a borehole. Such methods include deploying a dipole transmitter into the borehole to a depth of investigation, deploying an array of electromagnetic receivers outside of the wellbore, and measuring a response of the formation at the array of electromagnetic receivers deployed outside of the wellbore, for example at the surface. From the response of the formation a property of the formation can be determined based on the response of the formation measured at the array of electromagnetic receivers. For the scenario of a cased well, a local reference receiver may be added at a location proximate the borehole to measure the effective magnetic moment of the transmitter inside the casing, and normalize the formation response in order for a more accurate determination of a formation characteristic, such as resistivity.

Abstract: A chip on glass substrate includes a substrate, first, second, and third pads that are arranged on the substrate and that are electrically connected to an IC device, and first to fourth conductive patterns. A first conductive pattern is arranged on the substrate, has one end electrically connected to the first pad, and has another end that is electrically floated. Second and third conductive patterns are arranged on the substrate, each have one end electrically connected to the second pad, and each have another end that is electrically floated. A fourth conductive pattern is arranged on the substrate, has one end electrically connected to the third pad, and has another end that is electrically floated.

Abstract: Disclosed dielectric logging tools and methods employ three or more receive horn antennas positioned between at least two transmit antennas, which can also be horn antennas. The logging tools can operate in the range between 100 MHz and 10 GHz to provide logs of formation permittivity, formation conductivity, standoff distance, and electrical properties of material in the standoff gap. Logs of water-saturated porosity and/or oil movability can be readily derived. The presence of additional receive antennas offers a significantly extended operating range, additional depths of investigation, increased measurement accuracy, and further offers compensation for tool standoff and mudcake effects. In both wireline and logging while drilling embodiments, at least some disclosed dielectric logging tools employ a set of three axially-spaced receive antennas positioned between pairs of axially-spaced transmit antennas.

Abstract: A magnetometer for sensing a magnetic field may include a solid state electronic spin system, and a detector. The solid state electronic spin system may contain one or more electronic spins that are disposed within a solid state lattice, for example NV centers in diamond. The electronic spins may be configured to receive optical excitation radiation and to align with the magnetic field in response thereto. The electronic spins may be further induced to precess about the magnetic field to be sensed, in response to an external control such as an RF field, the frequency of the spin precession being linearly related to the magnetic field by the Zeeman shift of the electronic spin energy levels. The detector may be configured to detect output optical radiation from the electronic spin, so as to determine the Zeeman shift and thus the magnetic field.

Abstract: Provided are a metal detection method, a metal detection device, a metal detection method for a wireless power supply device, and a wireless power supply device which are capable of accurately detecting whether an object is a metal or a nonmetal. An oscillation circuit (10) oscillates and produces a sine wave having a single fundamental frequency, and excites a metal detection coil (Ls) by the oscillation current (It) of the sine wave. An electromagnetic wave of the sine wave having the single fundamental frequency is radiated from the metal detection coil (Ls). A high-pass filter circuit (11a) receives the oscillation current (It), removes the fundamental frequency component from the oscillation current (It), and extracts a high-harmonic component of the fundamental frequency. A comparison circuit (12) determines the presence or absence of a metal.

Abstract: Downhole tools and techniques acquire information regarding nearby conductors such as pipes, well casing, and conductive formations. At least some method embodiments provide a current flow along a drill string in a borehole. The current flow disperses into the surrounding formation and causes a secondary current flow in the nearby conductor. The magnetic field from the secondary current flow can be detected using one or more azimuthally-sensitive antennas. Direction and distance estimates may be obtainable from the azimuthally-sensitive measurements, and can be used as the basis for steering the drillstring relative to the distant conductor. Possible techniques for providing current flow in the drillstring include imposing a voltage across an insulated gap or using a toroid around the drillstring to induce the current flow.

Abstract: Methods and apparatuses for geophysical surveying are disclosed. In one embodiment, a marine vehicle may obtain magnetic measurements in a location around a drilling site. The magnetic measurements may be used to calculate a localized disturbance magnetic field resulting from, for example, solar flares. The localized disturbance magnetic field may be used to calculate a declination value and, thus, a wellbore position with improved accuracy.

Abstract: The present disclosure relates to methods and apparatuses for evaluating a porous earth formation. The method may include estimating a value of at least one parameter of interest of the earth formation using a signal indicative of acoustic waves generated at a metallic surface (200) in communication with the earth formation when the metallic surface (200) is exposed to a constant magnetic field (250) normal to the metallic surface (200) and a harmonic magnetic field (260) along the metallic surface. The signal may be generated by a sensor responsive to the acoustic waves. The apparatus may include a first magnetic source (230) configured to generate a constant magnetic field (250), a second magnetic source (240) configured to generate a harmonic magnetic field (260), and a sensor (220) configured to generate a signal in response to acoustic waves.

Abstract: A method of determining the maximum temperature undergone by a specimen of sedimentary rock during natural heating over a geological process, within the range from 60° C. to 230° C. approximately. The method includes analysis at very low temperature, down to a few kelvin, for example down to 10 kelvin, of the magnetic transitions intended to characterize an iron oxide and an iron sulfide that are formed or destroyed in the specimen by the geological heating of the sediment; and determination of the maximum temperature undergone by the specimen, using a calibration obtained by measuring the same magnetic parameters on the same sediment or on other sediments of the same nature, heated beforehand in the laboratory to known temperatures.

Abstract: A method and a downhole tool determine one or more parameters of a formation traversed by a borehole where at least a portion of the formation has substantially parallel boundaries. A tool is disposed in the borehole that includes a transmitter having a dipole moment at an angle ?T with respect to a longitudinal axis of the tool, a receiver having a dipole moment at an angle ?R with respect to the longitudinal axis of the tool and a rotational position indicator. The transmitter-receiver pair transmits an electromagnetic signal while rotating the tool, receives the electromagnetic signal to produce a measured signal, and determine(s) the formation parameters for the portion of the formation having substantially parallel boundaries based on the measured signal.

Abstract: A method for detecting hydrocarbons is described. The method includes performing a remote sensing survey of a survey location to identify a target location. Then, an underwater vehicle (UV) is deployed into a body of water and directed to the target location. The UV collects measurement data within the body of water at the target location, which is then analyzed to determine whether hydrocarbons are present at the target location.

Abstract: A method for mapping geological structures of a formation on a side of a surface, includes: generating a magnetic moment using at least one magnetic moment generator to build up a magnetic field in the formation in an on-period, wherein the magnetic moment has a moment strength, and wherein the magnetic moment is positioned on another side of the surface; changing the magnetic moment to change the magnetic field; and making at least one record in a recording device at a recording time trecord in an off-period, wherein the record includes at least a representation of the change in the magnetic field and/or a representation of the magnetic field obtained by a B/E-measuring unit; wherein the on-period is separated from the off-period by the act of changing the magnetic moment.

Abstract: A magnetic signal noise reduction and detection system has inputs configured to receive data from a first total field scalar magnetometer, data from a vector magnetometer, and data from a position, velocity and heading sensor, a signal processor configured with a pre-processor system, an adaptive noise cancellation system and a detection system, the pre-processor system configured to carry out initial processing of data received. The pre-processor is configured to convert data to the frequency domain and pass the converted data to the adaptive noise cancellation system. The adaptive noise cancellation system is configured to carry out multivariate regression on the converted data to reduce detected noise. The detection system is configured to detect magnetic anomalies and output information in real time about the magnetic anomalies to a user interface.

Abstract: The invention concerns a proximity detection of buried conductive structures before or while digging in areas being excavated. By means of the enclosed methods, devices, and setups, the ability and accuracy of the detection of underground structures, such as conduits, pipes, etc. is improved by conductively applying a current into the structure through the soil. The thereby emitted electromagnetic field is detected by a movable detection-unit over ground. According to this electromagnetic field the detection-unit can determine the proximity of the structure and issue a warning signal. This warning signal helps an operator of an earth moving machine to avoid a collision with the structure.

Abstract: A system and methods for facilitating drilling and/or drilling a well in an orientation with respect to an existing well are provided. Specifically, one method in accordance with present embodiments is directed to producing a magnetic field with a magnetic field source positioned in a non-magnetic region of casing within a first well, wherein the first well is cased with alternating regions of magnetic casing and non-magnetic casing. The method may also include producing at least one output from at least one magnetic field sensor capable of sensing directional magnetic field components, wherein the at least one output is based on detection of the magnetic field and wherein the at least one magnetic field sensor is positioned in a second well.

Abstract: A geomagnetic application device including a triaxial magnetic sensor, a measurement point acquiring mechanism, a calibration mechanism calibrating offset of the magnetic sensor, and an azimuth calculator. The calibration mechanism includes an offset calculation measurement point selector selecting at least six measurement points of the geomagnetic vectors from among a data set stored in the measurement point storage unit by the measurement point acquiring mechanism and storing the selected measurement points in an offset calculation measurement point storage unit. The offset calculation measurement point selector selects the measurement points from among the data set stored in the measurement point storage unit to include at least six points, component values of which are maximum or minimum in each of three orthogonal axes.

Abstract: A steerable or non-steerable, magnetic dipole antenna for Measurement-While-Drilling (MWD) or Logging-While-Drilling (LWD) applications. The antenna elements use a hole arrangement in addition to grooves in a steel tool body, which is typically a drill collar. This antenna embodiment is extremely robust, meaning that does not significantly reduce the structural integrity of the tool body in which it is disposed. The antenna embodiment is also relatively wear resistant. The resultant magnetic dipole generated by this antenna is also electrically steerable in inclination angle from a common origin. A variable dipole moment inclination angle combined with independently measured tool rotation orientation during normal drilling allows the antenna to generate a magnetic dipole moment that may be directed at any three dimensional angle and from a common origin point at the centroid of the antenna. The antenna can also be embodied to be more sensitive to resistivity in a particular azimuthal direction.

Abstract: A system and methods for drilling a well in a field having an existing well are provided. Specifically a method of drilling a new well in a field having an existing well includes drilling the new well using a bottom hole assembly (BHA) having a drill collar divided by an insulated gap, generating a current on the drill collar of the BHA while drilling the new well, and measuring from the existing well a magnetic field caused by the current on the drill collar of the BHA. Using measurements of the magnetic field, a relative position of the new well to the existing well may be determined.

Abstract: A geomagnetic application device including a triaxial magnetic sensor, a measurement point acquiring mechanism, a calibration mechanism calibrating offset of the magnetic sensor, and an azimuth calculator. The calibration mechanism includes an offset calculation measurement point selector selecting at least six measurement points of the geomagnetic vectors from among a data set stored in the measurement point storage unit by the measurement point acquiring mechanism and storing the selected measurement points in an offset calculation measurement point storage unit. The offset calculation measurement point selector selects the measurement points from among the data set stored in the measurement point storage unit to include at least six points, component values of which are maximum or minimum in each of three orthogonal axes.

Abstract: An underground electromagnetic exploration method using an induced current generating transmitter that cyclically generates an induced current includes repeating magnetic field observations at multiple measurement points on earth's surface, the magnetic field observations including observing a magnetic field including a magnetic field signal based on output from the induced current generating transmitter using a magnetic field sensor device including a sensor and a rod-shaped core; wherein the sensor includes a magneto-impedance device having a magnetic amorphous structure; and wherein the rod-shaped core guides a magnetic field to the magnetic amorphous structure and is disposed longitudinally along the magnetic amorphous structure, and storing magnetic field observational data including a magnetic field signal based on output from the induced current generating transmitter, and calculating an underground specific resistivity distribution based on the observational data corresponding to each measurement poin