| 摘要 |
A method of using an electromagnetic induction instrument in a borehole in an earth formation comprises changing a current through a transmitter on the instrument and inducing transient currents in the formation, receiving a temporal signal resulting from the induced current in at least one receiver on the instrument, said received temporal signal including effects of the conductive body of the instrument, and determining from a reference signal and the temporal signal a distance to an interface in the formation, the determination being substantially unaffected by the conductive body. Apparatus includes the conductive borehole instrument and processing means for determining the distance. The method and apparatus may be used to control drilling direction of a BHA. The reference signal is one measured in a homogenous medium. |
