Class / Patent application number | Description | Number of patent applications / Date published |
324355000 | Within a borehole | 54 |
20080272789 | Permittivity Measurements With Oil-Based Mud Imaging Tool - Oil-based mud imaging systems and methods that measure formation permittivity. In some embodiments, disclosed logging systems include a logging tool in communication with surface computing facilities. The logging tool is provided with a sensor array having at least two voltage electrodes positioned between at least two current electrodes that create an electric field in a borehole wall, and is further provided with electronics coupled to the voltage electrodes to determine a differential voltage magnitude and phase. From the magnitude and phase, formation resistivity and permittivity measurements can be determined and used to construct a borehole wall image. | 11-06-2008 |
20080278171 | Two-Axial Pad Formation Resistivity Imager - A resistivity imaging device injects currents in two orthogonal directions using two pairs of return electrodes and performing impedance measurements of the buttons placed between the returns. | 11-13-2008 |
20090001989 | ONE ROW WAVELET SENSOR LAYOUT FOR RESISTIVITY IMAGING - A sensor electrode for imaging a formation, includes a geometry that one of reduces or substantially limits spatial aliasing in formation data, the aliasing resulting from imaging the formation with an array of the sensor electrodes. A method and a computer program product for designing sensor electrodes are provided. A sensor with a one-row wavelet geometry is disclosed. | 01-01-2009 |
20090066336 | Apparatus and Method for Electrically Investigating a Borehole - An apparatus used in electrical investigation of geological formations GF surrounding a borehole BH, comprises:
| 03-12-2009 |
20090072833 | Resistivity Imaging Using Phase Sensitive Detection with a Floating Reference Signal - A device, method and system for measuring characteristics of a geologic formation using a floating reference signal having a mud chamber, an electrode disposed within the mud chamber, and an electrically conductive plate disposed within the mud chamber, the plate separated from the electrode. An alternating current source is provided on the electrode, whereby an electric field is be maintained between the electrode and the conductive plate. An opening in the mud chamber allows drilling fluids to pass there through. | 03-19-2009 |
20090243619 | FOUR-TERMINAL ELECTRIC IMAGER FOR RESISTIVE MUDS WITH LOCALIZED CURRENT CONTROL - An apparatus for imaging a subsurface material traversed by a borehole, the apparatus including an imaging pad deployed by a logging instrument, the pad including a plurality of measuring sets, each measuring set including a first current injector electrode, a second current injector electrode, a pair of sensor electrodes disposed between the first current injector electrode and the second current injector electrode, and an output for coupling to an electronics unit adapted for producing the imaging of the subsurface material. | 10-01-2009 |
20090256575 | ELECTROLOCATION APPARATUS AND METHODS FOR MAPPING FROM A SUBTERRANEAN WELL - In some embodiments, apparatus useful for determining at least one dimension of at least one geological feature of an earthen formation from a subterranean well bore includes at least two emitting electrodes and at least one sensing electrode disposed in the well bore. The emitting electrodes are configured to create an electric field and the at least one sensing electrode is configured to detect perturbations in the electric field created by at least one target object. | 10-15-2009 |
20090302854 | Apparatus for Formation Resistivity Imaging in Wells with Oil-Based Drilling Fluids - Sequential measurements are made using a two terminal resistivity imaging device wherein the measure electrodes are activated sequentially with the remaining electrodes in a floating mode. This eliminates the hardware requirements for focusing electrodes, prevents galvanic leakage between proximal electrodes and the effects of mutual coupling between circuits including proximal electrodes. | 12-10-2009 |
20090309602 | SEQUENTIAL RESISTIVITY IMAGING WITH ASYMMETRIC ELECTRODE ARRAYS - A method for providing a symmetric resistivity image of a formation using at least one asymmetric sensor, includes: collecting a plurality of resistivity images, each of the images collected from the at least one asymmetric sensor disposed on a pad; assembling the plurality of resistivity images about a selected reference point; and processing the plurality of resistivity images to provide a symmetric image of the formation. A computer program product and an instrument are disclosed. | 12-17-2009 |
20090322338 | METHODS AND APPARATUS FOR DETERMINING A PRESENCE OF A NON-CONDUCTIVE COATING ON ELECTRODES IN DOWNHOLE FLUID RESISTIVITY MEASUREMENT DEVICES - Methods and apparatus for determining a presence of a non-conductive coating on electrodes in fluid resistivity measurement devices are described. An example method of determining a presence of a non-conductive coating on electrodes of a fluid resistivity measurement device involves obtaining a first electrical potential value associated with a substantially uncoated condition of first and second electrodes of a fluid resistivity measurement device. The example method also involves measuring a second electrical potential value at a location between the first and second electrodes, comparing the first and second electrical potential values, and determining the presence of a non-conductive coating on at least one of the first and second electrodes based on the comparison. | 12-31-2009 |
20100019771 | Multi-Resolution Borehole Resistivity Imaging - 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, each of the plurality of sensor electrodes having a different capacitance to a wall of the borehole; 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. | 01-28-2010 |
20100019772 | CONCENTRIC BUTTONS OF DIFFERENT SIZES FOR IMAGING AND STANDOFF CORRECTION - A method of estimating standoff in a borehole through an earth formation, includes: disposing a sensor including a plurality of return electrodes and at least one transmitter electrode disposed in a concentric arrangement into the borehole; injecting current, I, into the formation by applying at least two frequencies of alternating current (AC) voltage between at least two of the electrodes; measuring impedance, Z, for each of the frequencies; and using a predetermined relationship between impedance, Z, and standoff, estimating the standoff. A system and a computer program product are provided. | 01-28-2010 |
20100026305 | Method and Apparatus for Imaging Boreholes - A method and apparatus for imaging wellbores is provided that in one aspect may include inducing an electrical signal into a formation, receiving a current signal responsive to the induced electrical signal by at least one measure electrode placed in a pad disposed in the wellbore, generating an impedance signal in response to the received current signal using a receiver circuit placed in the pad and coupled to the at least one measure electrode and providing an image of the wellbore wall using the impedance signal. | 02-04-2010 |
20100039115 | SYSTEM AND METHOD FOR MEASURING RESISTIVITY OF AN EARTH FORMATION WITH CORRECTION FOR MUD ELECTRICAL PROPERTIES - 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. | 02-18-2010 |
20100052690 | Formation Resistivity Imaging in Conductive Boreholes - An apparatus for providing an image of a resistivity property of an earth formation surrounding a borehole is provided. The apparatus, in one aspect, may include a plurality of measure electrodes that are configured to convey an electrical current into the earth formation. In one aspect, each measure electrode may be substantially surrounded by an associated insulator that extends away from a tool body in a manner that blocks at least a portion of a vertical current flowing in a conductive fluid when the tool is operated to log the borehole. A processor provides an image of the resistivity property of the earth formation using the current in plurality of measure electrodes. | 03-04-2010 |
20100271031 | Standoff-Independent Resistivity Sensor System - A contact subassembly on a downhole carrier is moved by torsion rod, rotation of which moves the contact assembly to the proximity of the borehole wall. Rotation of the torsion rod may be accomplished by a hydraulically powered piston-lever arrangement. The rotation of the torsion bar may be used to estimate the borehole size. The contact assembly may be provided with resistivity sensors, acoustic sensor for making VSP measurements while drilling, and a port for sampling a formation fluid. | 10-28-2010 |
20100295548 | METHODS AND APPARATUS FOR PROVIDING COMPLIMENTARY RESISTIVITY AND STANDOFF IMAGE - A method for presenting a formation property to a user includes estimating an initial property of the formation using a tool conveyed in a borehole and estimating a relationship between the tool and the formation based on information received from the tool. The method also includes presenting the user a first output based at least in part on the initial property and presenting a second output based at least in part on the relationship proximate the first output. | 11-25-2010 |
20110025335 | METHOD AND APPARATUS FOR GALVANIC MULTI-FREQUENCY FORMATION RESISTIVITY IMAGING - A formation measurement and processing technique which reduces the effects of standoff between a resistivity tool and a borehole wall where the resistivity tool utilizes capacitive coupling between the tool and the formation to obtain resistivity data useful to generate a resistivity image of the formation. Reduction of standoff effects is achieved through the use of multi-frequency, phase sensitive measurements to identify a measured resonance frequency that may be used to produce an image that utilizes measurements least affected by the tool standoff and unknown or unspecified inductance of the tool. Reduction of standoff effects are the most pronounced in the case of the low resistivity formations and oil-based, low-conductive drilling fluids. | 02-03-2011 |
20110140702 | Apparatus and Method for Balancing Impedance of a Resistivity Measuring Tool - An apparatus for making resistivity measurements of an underground formation surrounding a borehole, comprising:
| 06-16-2011 |
20110156708 | CONCENTRIC BUTTONS OF DIFFERENT SIZES FOR IMAGING AND STANDOFF CORRECTION - Disclosed is a method of estimating a property of an earth formation penetrated by a borehole. The method 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 | 06-30-2011 |
20110241689 | TOOL FOR IMAGING A DOWNHOLE ENVIRONMENT - The invention is concerned with a tool and method for imaging a formation through a substantially non-conductive medium. The tool comprises first circuitry for injecting a current into the formation, wherein a complex impedance to the current is measured. Second circuitry for determining a phase angle of an impedance of the non-conductive medium and third circuitry for determining a component of the complex impedance that is orthogonal to the phase angle. | 10-06-2011 |
20110241690 | TOOL FOR IMAGING A DOWNHOLE ENVIRONMENT - The invention is concerned with a tool and method for determining a downhole parameter. The tool is located in mud surrounded by a formation and comprising a first electrode spaced at a distance from the formation for measuring a first impedance. There is a second electrode located at a second distance from the formation for measuring a second impedance. There is a processing unit for measuring a difference between the first impedance and the second impedance and wherein the parameter is determined based on the difference. | 10-06-2011 |
20110248717 | Oil-Based Mud Imager With a Line Source - A resistivity imaging device uses a line source in conjunction with an array of measure electrodes to reduce sensitivity to tool standoff when use in a borehole with oil-based mud. | 10-13-2011 |
20120068713 | Resistivity Imaging Using Phase Sensitive Detection with a Floating Reference Signal - A device, method and system for measuring characteristics of a geologic formation using a floating reference signal having a mud chamber, an electrode disposed within the mud chamber, and an electrically conductive plate disposed within the mud chamber, the plate separated from the electrode. An alternating current source is provided on the electrode, whereby an electric field is be maintained between the electrode and the conductive plate. An opening in the mud chamber allows drilling fluids to pass there through. | 03-22-2012 |
20120074946 | Active Standoff Compensation in Measurements with Oil-Based Mud Resistivity Imaging Devices - 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. | 03-29-2012 |
20130043873 | APPARATUS AND METHODS FOR PROVIDING INFORMATION ABOUT ONE OR MORE SUBTERRANEAN FEATURE - A method of approximating or determining at least one dimension or other characteristic of at least one underground geological feature in a zone of interest proximate to a well bore includes generating an electric field in the zone of interest. At least two sensing electrodes are provided in the well bore and configured to detect differences therebetween in electric potential caused by at least one target object in the zone of interest. Proppant containing signal generating devices (SGD) is delivered into the geological feature(s). The SGD generate a detectable signal in response to at least one downhole condition or property. At least one receiver receives the detectable signals and provides data relating thereto. At least one dimension or other characteristic of the geological feature is approximated or determined based at least partially upon data provided by the sensing electrodes and receiver(s). | 02-21-2013 |
20130063150 | CONNECTION METHOD OF REPLACEABLE SENSORS FOR RESISTIVITY ARRAYS - An apparatus and method for conducting resistivity logging in a borehole. The apparatus may include a housing configured for fluid isolation, an electrical conductor penetrating the housing and a sealing interface. The apparatus may also include at least one of: an electrical component inside the housing and an electrode disposed on the exterior of the housing. The apparatus is configured to allow the electrical conductor to be moved, while maintaining the sealing interface, between an electrically connected state and an electrically disconnected state with at least one of: the electrical component and the electrode. The method may include using the apparatus for resistivity logging operations. | 03-14-2013 |
20130069656 | Borehole Resistivity Imager Using Discrete Energy Pulsing - A resistivity imager uses discrete energy pulsing to determine resistivity of a borehole. The imager has pulse generation circuitry that generates discrete energy pulses. An electrode array exposed to the borehole emits or discharges the discrete energy pulses into the formation. The variations of the formation subject the electrode to impedance levels in response to the discrete energy pulses, and measurement circuitry measures the discharge of the pulsed energy subjected to the impedances. From the measurements, control circuitry determines resistivity parameters of the formation around the borehole. These resistivity parameters can be stored in memory downhole or can be telemetered to the surface. When analyzed, the resistivity measurements can produce an image of the borehole's features, indicate borehole structures, direct geosteering of drilling, or the like. | 03-21-2013 |
20130106421 | Methods and Systems for Determining Standoff Between a Downhole Tool and a Geological Formation | 05-02-2013 |
20130134981 | CRYSTAL SENSOR MADE BY ION IMPLANTATION - Disclosed is a method for producing a crystal sensor. The method includes selecting a crystal configured to sense a property of interest. The method further includes implanting ions in the crystal using ion-implantation to produce a conductive region within the crystal where the conductive region is capable of providing a signal to sense the property of interest. Also disclosed is a method and apparatus for estimating a property of interest using the crystal sensor in a borehole penetrating the earth. | 05-30-2013 |
20130234718 | MULTI-ARRAY LATEROLOG TOOLS AND METHODS WITH DIFFERENTIAL VOLTAGE MEASUREMENTS - Multi-array laterolog tool systems and methods acquire a set of array measurements sufficient to provide laterolog tool measurements of differing array sizes. Such systems and method offer multiple depths of investigation while offering greater measurement stability in borehole environments having high resistivity contrasts. In at least some system embodiments, a wireline or LWD tool body has a center electrode positioned between multiple pairs of guard electrodes and a pair of return electrodes. The tool's electronics provide a current from the center electrode to the pair of return electrodes and currents from each pair of guard electrodes to the pair of return electrodes. Each of the currents may be distinguishable by frequency or distinguishable by some other means. This novel arrangement of currents provides a complete set of measurements that enables one tool to simultaneously emulate a whole range of laterolog tools. | 09-12-2013 |
20130257436 | Multi-Array Laterolog Tools and Methods - Multi-array laterolog tool systems and methods acquire a set of array measurements sufficient to provide laterolog tool measurements of differing array sizes. Such systems and method offer multiple depths of investigation while offering greater measurement stability in borehole environments having high resistivity contrasts. In at least some system embodiments, a wireline or LWD tool body has a center electrode positioned between multiple pairs of guard electrodes and a pair of return electrodes. The tool's electronics provide a current from the center electrode to the pair of return electrodes and currents from each pair of guard electrodes to the pair of return electrodes. Each of the currents may be distinguishable by frequency or distinguishable by some other means. This novel arrangement of currents provides a complete set of measurements that enables one tool to simultaneously emulate a whole range of laterolog tools. | 10-03-2013 |
20130293234 | System and Method for Measuring Downhole Parameters - Systems, tools and techniques for measuring downhole parameters are provided. The techniques involve providing a downhole tool with a sensing apparatus. The sensing apparatus has at least one source positionable about the downhole tool, at least one sensor electrode positionable about a front face of the downhole tool for measuring electrical signals from the source, and a raised insulating cover positionable along the front face of the downhole tool for defining at least one contact surface. The raised insulating cover extends over at least a portion of the sensor electrode whereby the sensor electrode is positionable adjacent to the subterranean formation for electrically coupling thereto without direct contact therewith. | 11-07-2013 |
20140132272 | Analyzing Subterranean Formation With Current Source Vectors - A method analyzes a subterranean formation. At least one property of a well casing in the subterranean formation is determined and a plurality of current source vectors at respective positions along a trajectory of the well casing are determined. The effect of the well casing is determined based upon the plurality of current source vectors and the at least one property of the well casing. | 05-15-2014 |
20140191762 | System and Method for Imaging Properties of Subterranean Formations - A system and method for imaging properties of subterranean formations in a wellbore is provided. The system comprises a formation sensor for collecting currents injected into the subterranean formations, the formation sensor positionable on a downhole tool deployable into the wellbore. The system comprises a controller for controlling the formation sensor and a formation imaging unit. The formation imaging unit comprises a current management unit for collecting data from the currents injected into the subterranean formations, the currents having at least two different frequencies. The formation imaging unit comprises a drilling mud data unit for determining at least one drilling mud parameter, a formation data unit for determining at least one formation parameter from the collected data, and an inversion unit for determining at least one formation property by inverting the at least one formation parameter. | 07-10-2014 |
20140197839 | Apparatus and Method for Balancing Impedance of a Resistivity Measuring Tool - Techniques related to making resistivity measurements of an underground formation surrounding a borehole involve using a tool having an insulating pad mounted on the conductive body of the tool. The pad has a current injector electrode and a current return electrode electrically isolated from each other and mounted on a face of the pad. The pad is positionable in use to be adjacent the wall of the borehole. At least two impedance ratios are determined. The first is the ratio of the electrical impedance between the current injector electrode and the tool body and the electrical impedance between the current return electrode and the tool body. The second is the ratio of the electrical impedance between the current injector electrode and the formation, and the electrical impedance between the current return electrode and the formation on the other hand. The tool is arranged such that in operation, the two impedance ratios are substantially equal and there is substantially no potential difference between the tool body and the formation. | 07-17-2014 |
20140239960 | System and Method for Imaging Properties of Subterranean Formations - A system and method for imaging properties of subterranean formations in a wellbore is provided. The system comprises a formation sensor for collecting currents injected into the subterranean formations, the formation sensor positionable on a downhole tool deployable into the wellbore. The system comprises a controller for controlling the formation sensor and a formation imaging unit. The formation imaging unit comprises a current management unit for collecting data from the currents injected into the subterranean formations, the currents having at least two different frequencies. The formation imaging unit comprises a drilling mud data unit for determining at least one drilling mud parameter, a formation data unit for determining at least one formation parameter from the collected data, and an inversion unit for determining at least one formation property by inverting the at least one formation parameter. | 08-28-2014 |
20140266214 | METHOD AND SYSTEM FOR MONITORING SUBSURFACE INJECTION PROCESSES USING A BOREHOLE ELECTROMAGNETIC SOURCE - A method and a system for providing electromagnetic measurement in a rock formation are provided. The system includes a borehole casing having a plurality of casing segments. At least two casing segments of the plurality of casing segments are electrically isolated from each other. The system further includes an electromagnetic source positioned on a surface of the earth. The electromagnetic source is connected to the at least two casing segments. The electromagnetic source is configured to energize the at least two casing segments so as to generate an electromagnetic field in the rock formation around the borehole casing. | 09-18-2014 |
20140306710 | MULTI-ARRAY LATEROLOG TOOLS AND METHODS WITH SPLIT MONITOR ELECTRODES - Multi-array laterolog tool systems and methods acquire a set of array measurements sufficient to provide laterolog tool measurements of differing array sizes. Such systems and method offer multiple depths of investigation while offering greater measurement stability in borehole environments having high resistivity contrasts. In at least some system embodiments, a wireline or LWD tool body has a center electrode positioned between multiple pairs of guard electrodes and a pair of return electrodes. At least some of the guard electrodes are positioned between component electrodes of associated split monitor electrodes that enable more accurate measurement of the guard electrode potential. The tool's electronics provide a current from the center electrode to the pair of return electrodes and currents from each pair of guard electrodes to the pair of return electrodes. Each of the currents may be distinguishable by frequency or distinguishable by some other means. | 10-16-2014 |
20140347056 | Method and System for Calibrating a Downhole Imaging Tool - System and methods of generating calibrated downhole images of a subterranean formation ( | 11-27-2014 |
20150061683 | MAPPING RESISTIVITY DISTRIBUTION WITHIN THE EARTH - 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. | 03-05-2015 |
20150061684 | BOREHOLE ELECTRIC FIELD SURVEY WITH IMPROVED DISCRIMINATION OF SUBSURFACE FEATURES - Errors produced in a borehole to surface electromagnetic (BSEM) survey by near surface electrical anomalies on the estimates of formation properties are reduced. The effects of variations in subsurface electrical resistivity near the surface are separated from electrical resistivity changes at locations in the formations of interest far from the measurement region. A survey system includes one or more electrodes to inject electrical current at formation depth within a borehole, one or more counter electrodes which collect such current on the surface of the earth, and one or more electrodes to inject current on the surface. A transmitter is selectively connectable to different sets of the electrodes to cause a current to flow between the selected electrode sets. The resultant fields from the current flow are sensed and processed. The effects of near surface anomalies are detectable in the data and removable from the survey data of interest regarding the formations. The survey data more accurately indicates formation features or properties of interest. | 03-05-2015 |
20150293254 | APPARATUS AND METHOD FOR DOWNHOLE RESISTIVITY MEASUREMENTS - A downhole tool includes a body having a longitudinal axis and bore therethrough, an array of longitudinal electrode segments separated by electrical insulators, wherein substantially an entire cross section of said body comprises at least one electrode segment, at least one longitudinal electrode configured to emit a first electrical current into said formation and measure said first emitted current, at least one longitudinal electrode segment configured to emit a second electrical current for directing said first emitted current into said formation, and at least one longitudinal electrode segment configured to receive said first emitted current returning from said formation. | 10-15-2015 |
20150338540 | DUAL MODE BALANCING IN OBM RESISTIVITY IMAGING - Methods, systems, and devices for evaluating an earth formation. Methods may include conveying the carrier into a formation borehole; and using measure electrodes, in one mode of measurement, to make current measurements by applying a voltage to each measure electrode in a first set of sensor arrays while making first current measurements; and applying another high frequency voltage to each measure electrode in a second set of sensor arrays while making second current measurements. Optionally, methods include using the measure electrodes, in another mode of measurement, to make further resistivity measurements by applying a voltage to each measure electrode in both sets of sensor arrays while making third current measurements. Methods include combining first current measurements, second current measurements, and third current measurements to simulate a virtual impedance for each measure electrode. Optionally, any two consecutive sensor arrays around the circumference of the tool body are in different sets. | 11-26-2015 |
20150346375 | Application-Specific Integrated Circuits for Downhole Applications - A downhole imaging tool operable to obtain measurement data associated with a subterranean formation at a frequency above about 100 kHz. An application-specific integrated circuit (ASIC) is conveyable with the downhole imaging tool and operable to perform at least one of data acquisition, signal processing, and signal transmission utilizing the measurement data obtained by the downhole imaging tool. | 12-03-2015 |
20160139292 | RESISTIVITY LOGGING TOOL WITH EXCITATION CURRENT CONTROL BASED ON MULTI-CYCLE COMPARISON - 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. | 05-19-2016 |
20160178784 | Device For Measuring Resistivity In A Wellbore | 06-23-2016 |
20160252644 | SHIELDING DEVICE FOR IMPROVING DYNAMIC RANGE OF ELECTROMAGNETIC MEASUREMENTS | 09-01-2016 |
324356000 | While drilling | 6 |
20090021262 | Non Polarized Contacts for Resistivity Measurements in Drill Cuttings Samples for Surface Logging While Drilling - Apparatus and probe for non-polarized contacts for resistivity measurements in drill cuttings. At least two probes having a highly conductive shell from non-corrosive metal in form of pipe and a wood and/or other fine channeled thread (grained) water filled that will be conductive when it is wet. | 01-22-2009 |
20100253355 | Measuring With Tuned Transmitters and Broadband Receivers - An untuned, broadband receiver antenna for an induction or propagation logging tool reduces tool complexity, antenna coupling, and cross-talk between conductors to the antenna assemblies. | 10-07-2010 |
20110199090 | TOOL FOR IMAGING A DOWNHOLE ENVIRONMENT - The invention is concerned with a tool and method for determining standoff from a formation though mud. The tool comprising a first electrode located at a distance from the formation for measuring a first impedance. A second electrode is located at a second distance from the formation for measuring a second impedance. A processing unit measures a difference between the first impedance and the second impedance, uses the difference to determine a conductivity of the mud and based thereon, determines the standoff of at least one of the first and the second electrode. | 08-18-2011 |
20120326723 | Apparatus and Method for Actively Balancing Impedance of A Resistivity Measuring Tool - 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. | 12-27-2012 |
20130293235 | Apparatus and Method for Measuring Electrical Properties of an Underground Formation - The present disclosure provides an apparatus and method for measuring electrical properties of an underground formation surrounding a borehole. The apparatus preferably comprises a downhole tool positionable in the borehole, a sensor pad positionable on the downhole tool, and a plurality of electrodes mounted on the sensor pad and configured to face a wall of the borehole. The apparatus further comprises an insulating layer extending over at least a portion of the plurality of electrodes facing the wall of the borehole. | 11-07-2013 |
20150362615 | APPARATUS AND METHODS FOR COMMUNICATING WITH A DOWNHOLE TOOL - An apparatus for communicating with a downhole tool includes a sensor body including at least two electrodes electrically insulated from one another and an external control device configured to engage the two electrodes. Detection circuitry connected to the two electrodes is configured to monitor an electrical status across the two electrodes, through the external control device, and upon detecting a change in electrical status that matches a predefined pattern, communicate a command to power management circuitry to alter a power status of the downhole tool. | 12-17-2015 |