OBM sensor with a loop antenna
AssigneeBaker Hughes Incorporated
InventorsMartin Folberth, Christian Fulda, Matthias Gorek
Life of this patent
Estimating the term…
Abstract
A method and apparatus for downhole resistivity imaging uses an antenna coupled to a power source through a directional coupler. Measured reflectivity values are indicative of the antenna impedance and the formation resistivity, particularly if some compensation is made for the antenna inductance.
Claims25
An apparatus for use in a borehole in an earth formation, the apparatus comprising:
- (a) a coupling device coupling a power source to an antenna which transmits an electromagnetic signal into the borehole;
- (b) a processor which determines from the transmitted electromagnetic signal and an electromagnetic signal reflected from a wall of the borehole a parameter of interest of the earth formation.
A method of determining a parameter of interest of an earth formation, the method comprising:
- (a) coupling a power source to an antenna which transmits an electromagnetic signal into the borehole;
- (b) determining from the transmitted electromagnetic signal and an electromagnetic signal reflected from a wall of the borehole the parameter of interest of the earth formation.
The method of claim 23 further comprising operating the power source at a frequency between about 1 MHz and 1000 Mhz.
A computer readable medium for analyzing data from a resistivity measuring device conveyed in a borehole in an earth formation, the resistivity device comprising:
- (a) an antenna that propagates an electromagnetic signal into the formation;
- and
- (b) circuitry that provides an output signal indicative of a reflectivity of a wall of the borehole;
- the medium comprising instructions that enable determination of a resistivity parameter of the earth formation from the output signal.
Dependencies are inferred from the claim text.