| US 7,501,829 B2 | ||
| Extra bucking coils as an alternative way to balance induction arrays | ||
| Andrei I. Davydychev, Sugar Land, Tex. (US); John F. Hunka, Sugar Land, Tex. (US); Thomas D. Barber, Houston, Tex. (US); Scott S. Chesser, Richmond, Tex. (US); Bulent Finci, Sugar Land, Tex. (US); Jingjing (Karen) Sun, Missouri City, Tex. (US); William B. Vandermeer, Houston, Tex. (US); and Richard D. Ward, LaPorte, Tex. (US) | ||
| Assigned to Schlumberger Technology Corporation, Sugar Land, Tex. (US) | ||
| Filed on Feb. 16, 2006, as Appl. No. 11/307,674. | ||
| Claims priority of provisional application 60/657174, filed on Feb. 28, 2005. | ||
| Prior Publication US 2006/0192562 A1, Aug. 31, 2006 | ||
| Int. Cl. G01V 3/28 (2006.01); G01V 3/18 (2006.01) | ||
| U.S. Cl. 324—334 [324/338] | 11 Claims |
| 1. An electromagnetic logging tool, comprising:
a support; and
at least one four-coil away disposed on the support, wherein the at least one four-coil away comprises: a transmitter, a bucking
coil, a receiver, and a trim coil, wherein the transmitter, the bucking coil, and the receiver form a predetermined array
that is substantially balanced, and the trim coil is adjustable for fine-tuning the array, wherein the bucking coil is configured
to eliminate direct coupling between the transmitter and receiver coils as calculated in the absence of the bucking and trim
coils, and wherein the trim coil is configured to eliminate direct coupling between the transmitter and receiver coils as
measured in the presence of the bucking coil and the absence of the trim coil.
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