| US 7,588,082 B2 | ||
| Downhole tool position sensing system | ||
| Jeffrey B. Lasater, Houston, Tex. (US) | ||
| Assigned to Halliburton Energy Services, Inc., Houston, Tex. (US) | ||
| Filed on Jul. 21, 2006, as Appl. No. 11/459,271. | ||
| Claims priority of provisional application 60/701688, filed on Jul. 22, 2005. | ||
| Prior Publication US 2007/0017705 A1, Jan. 25, 2007 | ||
| Int. Cl. E21B 47/00 (2006.01) | ||
| U.S. Cl. 166—255.1 [166/255.2; 175/40; 175/45] | 24 Claims |
| 9. A method of sensing the position of a downhole tool including:
providing a mandrel;
surrounding at least a portion of the mandrel with an inner sleeve, the mandrel being rotatable relative to the inner sleeve
and the outer circumference of the inner sleeve including more than one selected position organized in more than one set arranged
in spaced-apart radial planes of the inner sleeve;
surrounding at least a portion of the inner sleeve with an outer housing, the mandrel and inner sleeve being rotatable relative
to the outer housing;
placing magnets in at least two of the selected positions;
sensing at least one of the amplitude and polarity of the magnetic field for the selected positions with a magnetic sensor
corresponding to each set;
transmitting a signal indicative of the sensed magnetic field to an electronics system; and
processing the sensor signal to determine a magnet reference position of the inner sleeve relative to the outer housing.
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