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Class Information
Number: 324/375
Name: Electricity: measuring and testing > Of geophysical surface or subsurface in situ > Using electrode arrays, circuits, structure, or supports > Coupled to artificial current source > Including separate pickup of generated fields or potentials > For well logging > Using current focussing means > Including plural current focussing arrays
Description: Subject matter having more than one focussing electrode configuration on a single borehole tool.
Patents under this class:
| Patent Number |
Title Of Patent |
Date Issued |
| 7427863 |
Method and system for calculating resistivity of an earth formation |
Sep. 23, 2008 |
| 7388382 |
System for measuring Earth formation resistivity through an electrically conductive wellbore casing |
Jun. 17, 2008 |
| 7256582 |
Method and apparatus for improved current focusing in galvanic resistivity measurement tools for wireline and measurement-while-drilling applications |
Aug. 14, 2007 |
| 7151377 |
Permanent apparatus for monitoring a well by injecting current through the casing into the formations |
Dec. 19, 2006 |
| 7109719 |
Method and apparatus for azimuthal resistivity measurements in a borehole |
Sep. 19, 2006 |
| 7098664 |
Multi-mode oil base mud imager |
Aug. 29, 2006 |
| 6809521 |
Apparatus and method for wellbore resistivity measurements in oil-based muds using capacitive coupling |
Oct. 26, 2004 |
| 6653839 |
Electrical measurement apparatus and method for measuring an electrical characteristic of an earth formation |
Nov. 25, 2003 |
| 6426625 |
Apparatus for logging the resistivity of a geological rock formation |
Jul. 30, 2002 |
| 6373254 |
Method and apparatus for controlling the effect of contact impedance on a galvanic tool in a logging-while-drilling application |
Apr. 16, 2002 |
| 5852363 |
Methods and apparatus for measuring characteristics of a formation around a borehole using computed focusing |
Dec. 22, 1998 |
| 5708369 |
Capacitive measuring device |
Jan. 13, 1998 |
| 5396175 |
Method and apparatus for evaluating formation resistivity using focused annular and azimuthal electrodes |
Mar. 7, 1995 |
| 5343153 |
Well logging method and apparatus using passive azimuthal electrodes |
Aug. 30, 1994 |
| 5268641 |
Logging method and apparatus for measuring the Grondingen effect-corrected resistivity of earth formations |
Dec. 7, 1993 |
| 5036283 |
Method and apparatus for measuring the resistivity of earth formations using anti-parallel active and passive focussing electrodes |
Jul. 30, 1991 |
| RE32564 |
Apparatus for determining the resistivity of a subsurface earth formation at different lateral distances from a bore hole wall |
Dec. 15, 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 |
Apr. 21, 1987 |
| 4646026 |
Method and apparatus for measuring resistivity of an earth formation |
Feb. 24, 1987 |
| 4594552 |
Logging method and apparatus for measuring earth formation resistivity as well as arm mechanism for the same |
Jun. 10, 1986 |
| 4584675 |
Electrical measuring while drilling with composite electrodes |
Apr. 22, 1986 |
| 4524325 |
Dual guard type resistivity measuring apparatus |
Jun. 18, 1985 |
| 4335353 |
Method and apparatus for detecting an anomaly in a resistivity measurement of an earth formation |
Jun. 15, 1982 |
| 4319192 |
Deep and/or shallow electrical resistivity investigation suitable for dual resistivity-induction logging |
Mar. 9, 1982 |
| 4282486 |
Dual focused resistivity logging method and apparatus with dynamic range reduction |
Aug. 4, 1981 |
| 4278942 |
Seal and pressure balance system for an electrode-type logging sonde |
Jul. 14, 1981 |
| 4122387 |
Apparatus and method for simultaneously logging an electrical characteristic of a well formation at more than one lateral distance from a borehole |
Oct. 24, 1978 |
| 4110682 |
Well logging apparatus with pad-mounted array of vertical electrodes of different lengths for measuring the resistivity of the flushed zone |
Aug. 29, 1978 |
| 4019125 |
Well logging pad devices having selective differential relief |
Apr. 19, 1977 |
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