Patent application number | Description | Published |
20080197851 | Borehole Conductivity Simulator Verification and Transverse Coil Balancing - Calibration of the arrays of a multicomponent induction logging tool is achieved by positioning the tool horizontally above ground. The upper and lower housings of the tool are connected by a borehole conductivity simulator which as a resistance comparable to that of a borehole. Axial and radial positioning of the transmitter coils is done by monitoring outputs at receiver coils to achieve a minimum. | 08-21-2008 |
20080224706 | Use of Electrodes and Multi-Frequency Focusing to Correct Eccentricity and Misalignment Effects on Transversal Induction Measurements - A multicomponent induction logging tool uses a nonconducting mandrel. A central conducting member including wires that electrically connect at least one of the antennas to another of the antennas. Electrodes disposed about the transmitter antenna form a conductive path through a borehole fluid to the central conducting member. | 09-18-2008 |
20080246486 | Mutual Shielding of Collocated Induction Coils in Multi-Component Induction Logging Instruments - In a multicomponent logging tool, a coil is electrically isolated by open circuiting another, substantially orthogonal coil. | 10-09-2008 |
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 |
20080297160 | Borehole Conductivity Simulator Verification and Transverse Antenna Balancing - A reactance is introduced into a flow path of axial currents in an induction logging tool. The reactance may be a capacitor or an inductor. A transmitter antenna is operated at a frequency defined by a cutoff frequency related to the reactance. | 12-04-2008 |
20080303525 | SINGLE-DIPOLE HIGH FREQUENCY ELECTRIC IMAGER - A single-dipole sensor for determining an electrical property of an earth formation, includes a pad consisting essentially of a body and at least one small electrode separated from a large electrode by an insulator; wherein an output of the sensor includes a measurement of an electrical signal through the formation for each small electrode. A method for using the sensor is included, as well as a method for providing images of the earth formation. | 12-11-2008 |
20090009174 | Borehole Conductivity Simulator Verification and Transverse Coil Balancing - Calibration of the arrays of a multicomponent induction logging tool is achieved by positioning the tool horizontally above ground. The upper and lower housings of the tool are connected by a borehole conductivity simulator which as a resistance comparable to that of a borehole. Axial and radial positioning of the transmitter coils is done by monitoring outputs at receiver coils to achieve a minimum. | 01-08-2009 |
20090084185 | ELECTROMAGNETIC ACOUSTIC TRANSDUCER WITH CROSS-TALK ELIMINATION - The electromagnetic acoustic transducer (EMAT) transducer disclosed herein is useful for the non-destructive analysis of objects. The transducer comprises a core having a winding and a coil disposed between the core and the object to be analyzed. One transducer can be used as a transmitter and another transducer as a receiver. Then selectively switching static magnetic field in either transmitter or receiver and processing data with and without static magnetic field allows for eliminating artifacts due to parasitic coupling between the transmitter/receiver pair. The switching of the static magnetic field can be implemented either by using electromagnet or a pair of permanent magnets where magnetization of one permanent magnet is reversed to provide cancellation of the static magnetic field. | 04-02-2009 |
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 |
20090306896 | 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 |
20100052687 | High Resolution Resistivity Earth Imager - An imaging tool made includes a pad whose curvature is chosen based on the expected range of borehole radius and the pad size so as to maintain the maximum standoff below a desired value. The curvature may be adjusted using fasteners. | 03-04-2010 |
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 |
20100109672 | Transient EM for Geosteering and LWD/Wireline Formation Evaluation - A transmitter on an instrument is used to induce currents in an earth formation when it is turned on or off. A Fourier transform is applied to transient measurements made in the receivers. A multifrequency focusing of the transformed data is used for applications like determination of a distance to an interface in the formation, controlling the drilling direction, determination of formation resistivities and formation strike directions. | 05-06-2010 |
20110001481 | Borehole Effect Reduction in Multi-Axial Induction - An apparatus, method and computer-readable medium are provided for estimating a resistivity property of an earth formation. A logging tool includes a first antenna arrangement and a second antenna arrangement of the logging tool; and at least one device for maintaining the first antenna arrangement and the second antenna arrangement in proximity to a wall of the borehole. The first antenna arrangement and the second antenna arrangement may be at substantially the same axial location on the logging tool. Alternately, the first antenna arrangement and the second antenna arrangement may be at different axial positions on the logging tool. Extendible arms of the logging tool are configured to extend one or more of the first antenna arrangement and the second antenna arrangement against a face of the borehole. | 01-06-2011 |
20110102023 | CURRENT-TO-VOLTAGE CONVERTERS WITH DYNAMIC FEEDBACK - An apparatus for modifying an output signal indicative of a downhole parameter that may include a carrier conveyable in a wellbore; a negative error compensator; and an output signal device. The negative error compensator may be configured to modify the output of the device to increase or decrease a characteristic of the output signal from the output signal device. Also, a method for modifying an output signal indicative of a downhole parameter that may include modifying a characteristic of an output signal produced by a output signal device in a wellbore using a negative error compensator. | 05-05-2011 |
20120068711 | PAD DEVICE FOR RESISTIVITY IMAGING IN THE WELLS WITH OIL BASED DRILLING FLUID - An apparatus and method for reducing coupling between at least one measure electrode and at least one return electrode in a logging tool in a borehole with non-conductive drilling fluid using a conductive shield disposed between the at least one measure electrode and the at least one return electrode. The apparatus may be configured to impart an electrical current into a formation and to receive a return current from the formation. The method may include using the apparatus. | 03-22-2012 |
20120169344 | USE OF ELECTRODES AND MULTI-FREQUENCY FOCUSING TO CORRECT ECCENTRICITY AND MISALIGNMENT EFFECTS ON TRANSVERSAL INDUCTION MEASUREMENTS - A multicomponent induction logging tool uses a nonconducting mandrel. A central conducting member including wires that electrically connect at least one of the antennas to another of the antennas. Electrodes disposed about the transmitter antenna form a conductive path through a borehole fluid to the central conducting member. | 07-05-2012 |
20120274329 | Imaging in Oil-Based Mud by Synchronizing Phases of Currents Injected Into a Formation - Disclosed is an apparatus for estimating a property of an earth formation penetrated by a borehole. The apparatus includes a carrier configured to be conveyed through the borehole. A first transmitter electrode and a second transmitter electrode are disposed at the carrier and configured to inject an electrical current into the earth formation. A first measurement electrode and a second measurement electrode are disposed at the carrier and configured to measure the electrical current to estimate the property of the earth formation. A first bucker amplifier is coupled to the first measurement electrode and a second bucker amplifier is coupled to the second measurement electrode, wherein the first and second bucker amplifiers are configured to equalize electrical potentials of areas in front of the first and second measurement electrodes. | 11-01-2012 |
20120299595 | HIGH RESOLUTION RESISTIVITY EARTH IMAGER - An imaging tool made includes a pad whose curvature is chosen based on the expected range of borehole radius and the pad size so as to maintain the maximum standoff below a desired value. The curvature may be adjusted using fasteners. | 11-29-2012 |
20130024119 | FORMATION RESISTIVITY MEASUREMENTS USING MULTIPLE CONTROLLED MODES - Disclosed is an apparatus for estimating a property of an earth formation penetrated by a borehole. The apparatus includes a plurality of electrodes disposed downhole and configured to inject an electrical current into the earth formation using an applied voltage and/or measure electrical current resulting from an injection of the electrical current. The apparatus also includes a processor configured to perform a series of formation measurements that include injecting current into the earth formation using a unique subset of electrodes in the plurality of electrodes and measuring current in the earth formation using one or more electrodes not used for the current injecting. The processer sums the measured currents for the electrodes wherein the sum of electrical currents for at least one electrode that measured electrical current is substantially in phase with the applied voltage; and uses the sum of in phase currents to estimate the property. | 01-24-2013 |
20130027045 | FORMATION RESISTIVITY MEASUREMENTS USING PHASE CONTROLLED CURRENTS - Disclosed is an apparatus for estimating a property of an earth formation penetrated by a borehole. The apparatus includes a carrier configured to be conveyed through the borehole and having a first transmitter electrode configured to inject electrical current into the formation and a first measurement electrode configured to receive electrical current for measurement due to the current injection in order to estimate the property of the earth formation. A controller is configured to determine a phase difference between injected electrical current and received electrical current. A first bucker amplifier is coupled to the first measurement electrode and configured to apply a voltage to the first measurement electrode based on the determined phase difference in order for a phase of current received by the first measurement electrode to be substantially in phase with the current injected by the first transmitter electrode. | 01-31-2013 |
20130030707 | APPARATUS AND METHOD FOR FORMATION RESISTIVITY MEASUREMENTS IN OIL-BASED MUD USING A FLOATING REFERENCE SIGNAL - Disclosed is an apparatus for estimating a property of an earth formation penetrated by a borehole containing an oil-based drilling fluid. The apparatus includes an electrode disposed at a carrier and configured to inject alternating current into the formation. An electrically conductive plate is disposed between the first electrode and a borehole wall. An electrical insulator is disposed between and contacts the first electrode and the conductive plate. The apparatus is configured to prevent the drilling fluid from being disposed between the first electrode and the conductive plate. A first sensor is used to measure an electric field established between the first electrode and the conductive plate. A processor is configured to receive a measurement of the electric field to use as a floating reference signal to determine a phase difference with respect to a measured electrical quantity related to the injected electrical current in order to estimate the property. | 01-31-2013 |
20130043884 | METHOD AND APPARATUS FOR CALIBRATING DEEP-READING MULTI-COMPONENT INDUCTION TOOLS WITH MINIMAL GROUND EFFECTS - An apparatus and method for calibrating a multi-component induction logging tool. The method may include orienting a Z-transmitter coil to be substantially orthogonal to at least one Z-receiver coil, positioning an X-transmitter coil disposed on the logging tool so that the X-transmitter coil is substantially parallel to a conducting surface; encompassing the Z-transmitter coil, the X-transmitter coil, and at least one Z-receiver coil of the logging tool with at least one conducting loop of a calibrator; and calibrating the logging tool using the calibrator. The apparatus may include a calibrator configured to receive the logging tool. The Z-transmitter coil and the Z-receiver coil may be located on separate subs that are detachable from one another. | 02-21-2013 |
20130066557 | METHOD OF PHASE SYNCHRONIZATION OF MWD OR WIRELINE APPARATUS SEPARATED IN THE STRING - The present disclosure is related to apparatuses and methods for estimating a phase offset in earth formations. The method may include estimating the phase offset by comparing signals generated and received by a first sub, the second signal being transmitted by a second sub that has been synchronized by the signal generated by the first sub. The signals may be exchanged using a first antenna on the first sub and a second antenna on the second sub. The signals may use a selected frequency. Synchronization may take place without electrical communication between the first and second subs. The method may include compensating for a propagation delay in the signals using the phase offset. The method may include using a time stamp during the synchronization. The apparatus may include a first antenna and a second antenna on first and second subs, respectively, both configured to transmit and receive electromagnetic signals. | 03-14-2013 |
20140111212 | 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. | 04-24-2014 |