Matches 101 - 150 out of 434 < 1 2 3 4 5 6 7 8 9 >


Match Document Document Title
8014963 Correction of sensor non-equipotentiality in a resistivity imaging device  
A method for correcting data from a sensor electrode in a sensor includes determining a potential difference (V) between the sensor electrode and another sensor electrode; from the potential...
8008919 Method for compensating drill pipe and near-borehole effect on and electronic noise in transient resistivity measurements  
Transient measurements made at two spaced apart receivers responsive to separate activation of two transmitters symmetrically disposed about the two receivers. The transmitters and receivers are...
7994790 Electromagnetic and magnetostatic shield to perform measurements ahead of the drill bit  
A transmitter on a bottomhole assembly (BHA) is used for generating a transient electromagnetic signal in an earth formation. A pair of receivers on the BHA receive signals that are indicative of...
7990153 Compensated directional resistivity measurements  
A method for making directional resistivity measurements includes sequentially transmitting first and second axial and transverse electromagnetic waves in a borehole and receiving substantially...
7991555 Electromagnetic directional measurements for non-parallel bed formations  
An orientation vector, referred to hereinafter as the “geosteering vector,” is directed to the more conductive formation area within the DOI of the tool and away from the more resistive formation...
7986144 Sensor and insulation layer structure for well logging instruments  
A logging sonde includes a tube defining a sealed chamber inside. An isolation layer is disposed on an exterior of the tube. At least one sensor is disposed on an exterior of the isolation layer....
7973532 Downhole spread spectrum induction instruments  
A plurality of transmitters on a logging tool are activated simultaneously at substantially the same frequency. When the transmitter outputs are phase-modulated using a mutually orthogonal set of...
7952358 Methods and apparatus for determination of a formation resistivity property using eccentered measurements  
Multi-component induction measurements are made using a resistivity logging tool in an anistropic earth formation. The X-signal (quadrature) is insensitive to borehole eccentricity. A subset of...
7912648 Method and apparatus for imaging bed boundaries using azimuthal propagation resistivity measurements  
A method for imaging a geologic deposit using data collected from a borehole includes: selecting an instrument for performing electromagnetic (EM) measurements, the instrument including at least...
7902827 Method and apparatus for combined induction and imaging well logging  
An induction logging device is provided with additional electrodes. One set of electrodes provides voltages that are indicative of the current distribution in the borehole. The output of the first...
7898494 Locating technique and apparatus using an approximated dipole signal  
Location determination is performed using a transmitter including an elongated generally planar loop antenna defining an elongation axis. The elongation axis is positioned along at least a portion...
7888940 Induction resistivity cover  
A downhole induction resistivity assembly that comprises a downhole tool string component. The tool string component comprises an induction transmitter. The transmitter is adapted to induce an...
7852087 Removing effects of near surface geology from surface-to-borehole electromagnetic data  
A method that involves developing an electromagnetic property model of a near surface area and using this electromagnetic property model and electromagnetic data acquired using one or more...
7848887 Making directional measurements using a rotating and non-rotating drilling apparatus  
A system and method to determine directional measurements for a drilling tool that at times rotates and at other times does not rotate. The method includes making a first set of measurements when...
7839148 Method and system for calibrating downhole tools for drift  
A method and related system calibrating downhole tools for drift. Some of the illustrative embodiments are a logging tool comprising a tool body, a transmitter antenna associated with the tool...
7839346 Ruggedized multi-layer printed circuit board based downhole antenna  
The specification discloses a printed circuit board (PCB) based ferrite core antenna. The traces of PCBs form the windings for the antenna, and various layers of the PCB hold a ferrite core for...
7834631 Locating arrangement and method using boring tool and cable locating signals  
An arrangement and an associated method are described in which a boring tool is moved through the ground within a given region along a path in which region a cable is buried. The boring tool and...
7816921 Resistivity tools with load-bearing azimuthally sensitive antennas and methods of using same  
The disclosure provides apparatus and method for estimating an electrical property downhole. The apparatus, in one aspect, includes an antenna that comprises a unitary metallic member that has a...
7812608 Extra bucking coils to balance induction arrays  
An electromagnetic logging tool is disclosed that includes a support; and at least one four-coil array disposed on the support, wherein the at least one four-coil array comprises: a transmitter, a...
7812610 Method and apparatus for locating well casings from an adjacent wellbore  
A wellbore tool for locating a target wellbore containing a conductive member from a second wellbore and directing the trajectory of the second wellbore relative to the target wellbore includes an...
7800372 Resistivity tools with segmented azimuthally sensitive antennas and methods of making same  
In one aspect, an apparatus and a method for estimating one or more electrical properties downhole are provided. The apparatus, in one embodiment, may include a metallic member that has a...
7795872 Determining correction factors representing effects of different portions of a lining structure  
To determine effect on a magnetic field caused by a lining structure in a wellbore, an array may be deployed into the wellbore lined with the lining structure. The array comprises a plurality of...
7778778 Correction of multi-component measurements for tool eccentricity in deviated wells  
Measurements made by a multi-component induction logging tool are corrected for tool eccentricity in a deviated borehole. The eccentricity angle is determined from single frequency skin-effect...
7769572 Method of imaging subsurface formations using a virtual source array  
This invention relates generally to a method of simulating the signal of an electromagnetic source using one or more dipole sources. In the method a dipole source is located at an excitation...
7765067 Geosteering in earth formations using multicomponent induction measurements  
A multicomponent induction logging tool is used on a MWD bottomhole assembly. Multifrequency focusing that accounts for the finite, nonzero, conductivity of the mandrel is applied. Using...
7759940 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.
7746076 Method for imaging subterranean formations  
A method for using a tool in a wellbore in a formation to predict an anomaly in the formation ahead of the device, the tool comprising a transmitter for transmitting electromagnetic signals...
7742008 Multipole antennae for logging-while-drilling resistivity measurements  
A multipole antenna for conducting logging-while-drilling (LWD), includes a wire for one of producing and receiving an electromagnetic field, the wire having at least one winding for providing a...
7737697 Method and apparatus for use of the real component of a magnetic field of multicomponent resistivity measurements  
Multi-component induction measurements are made using a resistivity logging tool in an anistropic earth formation. A subset of the multi-component measurements are inverted to first determine...
7723989 Transducer assemblies for subsurface use  
Transducer apparatus for subsurface use. A tubular configured for subsurface disposal is equipped with a cylindrical transducer module formed of a non-conductive material. The module is mounted to...
7723991 Apparatus and method for azimuthal MWD resistivity imaging at multiple depths of investigation  
A combination of a shallow-reading and a deep-reading, azimuthally sensitive, multiple propagation devices is used for providing depth images the earth formation with different depth of...
7719282 Method and apparatus for mulit-component induction instrument measuring system for geosteering and formation resistivity data interpretation in horizontal, vertical and deviated wells  
An improved induction tool for evaluating formation resistivity. The tool provides electromagnetic transmitters and sensors suitable for transmitting and receiving magnetic fields in radial...
7714585 Multi-frequency cancellation of dielectric effect  
Measurements made with an induction logging tool are responsive to formation conductivity and permittivity. The effect of permittivity can be substantially removed by multifrequency focusing.
7692428 Retrievable formation resistivity tool  
Systems and methods for downhole communication and measurement utilizing an improved metallic tubular having an elongated body with tubular walls and a central bore adapted to receive a run-in...
7667464 Time segmentation of frequencies in controlled source electromagnetic (CSEM) applications  
A method for measuring a resistivity of a subsurface formation that includes transmitting continuously a signal at a first fundamental frequency at full power for a first period of time within a...
7663373 Determining beacon location using magnetic field ratios  
A method and system for identifying a location of a magnetic field source. A total magnetic field is measured during a calibration routine prior to a drilling procedure. During the drilling...
7660671 Method and apparatus for electromagnetic logging of a formation  
Using an electromagnetic logging tool, desired antenna responses are synthesized from a combination of measured antenna responses, as well as antenna arrays particularly suited to provide the...
7659723 Broadband resistivity interpretation  
Resistivity measurements are made at a plurality of frequencies. An asymptotic high-frequency limit is determined and the electrical efficiency is estimated as a ratio of the high frequency...
7657377 Azimuthal measurement-while-drilling (MWD) tool  
Various systems and methods determine a distance, magnitude, and azimuthal angle describing the location of an anomaly within a geologic formation. For example, a method involves identifying an...
7652478 Cross-component alignment measurement and calibration  
A multicomponent induction logging tool is positioned within an alignment loop and the transmitter is activated at a number of rotation angles of the tool. Misalignment between the transmitter and...
7626393 Apparatus and method for measuring movement of a downhole tool  
An apparatus for detecting movement downhole includes a first downhole component (106) having a sensor (114) coupled thereto and a second downhole component (102) positioned relative to the first...
7619540 Apparatus and methods for determining isotropic and anisotropic formation resistivity in the presence of invasion  
A logging tool includes a tool body; a simple transmitter comprising a single antenna disposed on the tool body; four simple receivers, each comprising a single antenna, disposed on the tool body...
7609065 System and method for locating an anomaly  
A method and a system are provided for allowing determination of a direction and distance from a tool to anomaly in a formation. The apparatus for performing the method includes at least one...
7595636 Apparatus and method of using accelerometer measurements for casing evaluation  
A casing inspection device with magnets and flux sensors. Measurements of axial motion of the device are used to get better definition of the axial extent of casing defects. A contact device may...
7586307 Locating arrangement and method using boring tool and cable locating signals  
An arrangement and an associated method are described in which a boring tool is moved through the ground within a given region along a path in which region a cable is buried. The boring tool and...
7583085 Downhole sensor assembly  
In one aspect of the invention, a sensor assembly for incorporation into a downhole tool string comprises at least one sensor adapted to detect changes in magnetic flux proximate a first portion...
7576543 Apparatus and method for resistivity measurements during rotational drilling  
A resistivity sub including a resistivity sensor forms part of a bottom hole drilling assembly. The sensor is maintained at a substantially fixed offset from the wall of a borehole during drilling...
7567869 Induction tool for detail evaluation of near borehole zone  
Measurements made with an induction logging tool are processed to provide a resistivity model of fluid invasion of the formation. Up to five zones can be determined over a radial distance of about...
7557582 Logging while drilling tool for obtaining azimuthally sensitive formation resistivity measurements  
An apparatus for making azimuthally sensitive resistivity measurements of a subterranean formation is disclosed. The apparatus includes a magnetically permeably ring deployed about an electrically...
7557581 Method for imaging subterranean formations  
A method of imaging a subterranean formation traversed by a wellbore using a tool comprising a transmitter for transmitting electromagnetic signals through the formation and a receiver for...

Matches 101 - 150 out of 434 < 1 2 3 4 5 6 7 8 9 >