Class 324/371 - Using plural fields

Subclass of Class 324 - Electricity: measuring and testing
Definition: Subject matter having means for creating more than one field
No. of patents: 20
Last issue date: 04/29/2008

Number	Title	Issue Date
7365545	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. ...	04/29/2008
7227363	Determining formation anisotropy based in part on lateral current flow measurements Disclosed herein are methods and apparatus using one or more toroids to measure formation anisotropy and/or vertical conductivity. In one embodiment, a disclosed method comprises: inducing a current to flow through a conductive surface of a tool body into a surround...	06/05/2007
7156169	Electrically operated actuation tool for subsea completion system components An electrically operated actuation tool for a subsea completion system component having at least one hydraulically actuatable mechanism comprises an electric motor, a hydraulic pump which is driven by the motor and at least one hydraulic line which communicates betw...	01/02/2007
7026820	Method and apparatus for minimizing direct coupling for downhole logging devices A method and apparatus for minimizing direct coupling between transmitters and receivers on a downhole logging tool are disclosed. One embodiment includes a transmitter, a bucking device, and a plurality of receivers, where signals may be directly coupled from the t...	04/11/2006
6765386	Galvanic method of measuring electrical anisotropy A logging tool is disclosed for measuring the resistive anisotropy of formations around a borehole. The logging tool includes a set of electrodes that contact a wall of the borehole. The set of electrodes includes a first pair of current electrodes spaced apart vert...	07/20/2004
6670813	Integrated borehole system for reservoir detection and monitoring A method is disclosed for generating an image of earth formations penetrated by a wellbore. The method includes generating an initial model of the earth formations using formation resistivity measured by a direct current signal. A response to the initial ...	12/30/2003
6603314	Simultaneous current injection for measurement of formation resistance through casing A method of determining resistivity of an earth formation through a conductive wellbore casing. The resistance of conductors within an armored electrical cable for a wellbore sonde is measured and the sonde is inserted into the wellbore. The sonde has a p...	08/05/2003
6541975	Integrated borehole system for reservoir detection and monitoring In one embodiment the invention comprises a system for generating an image of an Earth formation surrounding a borehole penetrating the formation. Resistivity of the formation is measured using a DC measurement, and conductivity and resistivity of the for...	04/01/2003
6426625	Apparatus for logging the resistivity of a geological rock formation A small diameter tool for measurement of resistivity of geological rock formations, including a complex auxiliary electrode structure which is adjustable in electrode length between deep and shallow mode measurement operations....	07/30/2002
6353322	Method for automatically calibrating resistivity well logs for effects of change in wellbore diameter and circuit drift A method for determining the resistivity of earth formations penetrated by a wellbore. Electrical current is imparted to the wellbore and the earth formations from a first electrode located on a mandrel disposed in the wellbore. The electrical current is ...	03/05/2002
6191588	Methods and apparatus for imaging earth formation with a current source, a current drain, and a matrix of voltage electrodes therebetween The borehole imaging apparatus of the present invention includes a tool having an array of voltage electrode buttons mounted on a non-conductive pad. A current source and a current return are preferably located on the non-conductive pads at opposite ends ...	02/20/2001
5754050	Method and apparatus for measuring geometrical characteristics of a well, in particular a hydrocarbon well A method and apparatus for evaluating the geometrical characteristics of a well, comprising insertion of a sonde (12) of elongate shape into the well, the sonde including azimuth electrodes (Aazi), an annular current electrode (A0), ...	05/19/1998
5680049	Apparatus for measuring formation resistivity through a conductive casing having a coaxial tubing inserted therein An apparatus for measuring the resistivity of earth formations penetrated by a wellbore having a conductive conduit. The apparatus includes an elongated sonde mandrel, a plurality of electrodes positioned at axially spaced apart locations along the mandre...	10/21/1997
5543715	Method and apparatus for measuring formation resistivity through casing using single-conductor electrical logging cable A method of determining resistivity of an earth formation penetrated by a wellbore having conductive casing. The preferred embodiment includes inserting a sonde into the wellbore, the sonde having a plurality of electrodes at axially spaced apart location...	08/06/1996
5075626	Electronic measurement apparatus movable in a cased borehole and compensating for casing resistance differences Methods of operation of an apparatus having at least two pairs of voltage measurement electrodes vertically disposed in a cased well to measure the resistivity of adjacent geological formations from inside the cased well. During stationary measurements wi...	12/24/1991
4851781	Method and apparatus for investigating a borehole using an array of elements A method and apparatus investigating a circumferential segment of a borehole with an array of elements, which in effect spatially samples the segment, is described whereby, with a single circumferentially oriented array of spaced-apart elements sufficient...	07/25/1989
4686477	Multiple frequency electric excitation method and identifying complex lithologies of subsurface formations A method of identifying complex lithologies of subsurface rock formations includes the excitation of at least a portion of the rock formation with a multi-frequency electric current. The voltage resulting in the rock is measured and the phase and amplitud...	08/11/1987
4659993	Apparatus including an equipotential housing and plurality of focused current electrodes for electrically logging a well formation at more than one lateral distance from a borehole An apparatus and a method are disclosed wherein simultaneous electrical well logs can be made with a plurality of focused currents emitted from a plurality of electrodes located along a single equipotential surface of a housing. The focused currents are g...	04/21/1987
4435806	Device for testing a circuit comprising sequential and combinatorial logic elements A device for processing digital signals includes combinatorial and sequential logic elements. For the testing of the device, a shift register can be formed from the sequential elements. A test pattern is applied thereto. The result of the processing of th...	03/06/1984
4282486	Dual focused resistivity logging method and apparatus with dynamic range reduction Method and apparatus for reducing the dynamic range of measure signals encountered in simultaneously obtaining two focused logs of formation resistivity with different depths of investigation and means for providing the required electrical connections of ...	08/04/1981

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Class 324/371 - Using plural fields