| US 7,568,532 B2 | ||
| Electromagnetically determining the relative location of a drill bit using a solenoid source installed on a steel casing | ||
| Arthur F. Kuckes, Ithaca, N.Y. (US); and Rahn Pitzer, Ithaca, N.Y. (US) | ||
| Assigned to Halliburton Energy Services, Inc., Houston, Tex. (US) | ||
| Filed on Dec. 04, 2006, as Appl. No. 11/607,887. | ||
| Claims priority of provisional application 60/810696, filed on Jun. 05, 2006. | ||
| Claims priority of provisional application 60/814909, filed on Jun. 20, 2006. | ||
| Prior Publication US 2007/0278008 A1, Dec. 06, 2007 | ||
| Int. Cl. E21B 47/01 (2006.01); E21B 47/022 (2006.01) | ||
| U.S. Cl. 175—40 [175/45; 166/255.2] | 33 Claims |
| 1. Apparatus for measuring the distance and direction between two boreholes extending into the Earth, comprising:
a solenoid assembly installed at a first selected point in a first borehole, said first borehole having a known inclination
and direction at said selected point;
down hole circuitry for energizing said solenoid assembly to generate a characteristic known solenoid field for a short interval
of time;
electronic circuitry in said solenoid assembly which actively waits for an initiating signal and upon receipt of said initiating
signal starts a prescribed electric current flow into said solenoid;
a magnetic field sensor deployed at a second selected point in a second borehole, said field sensor measuring three vector
components of said characteristic solenoid magnetic field at said second point;
orientation circuitry for determining a spatial orientation of said magnetic field sensor at said second point in said second
borehole; and
a processor responsive to said spatial orientation of said sensor and to said measured vector components at said second point
in said second borehole and further responsive to said characteristic known solenoid magnetic field to determine the distance
and direction between said first and second points.
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