FIELD: physics, measurement technology.
SUBSTANCE: probing and reference signals are generated. The reference signal has a lower frequency than the probing signal. The reference signal is transmitted through a geologic rock for reception by a device for measuring range in a reference well, wherein the probing signal is emitted downwards through the target well. The reference signal is reconstructed in the reference well, as well as a signal which is a combination of the probing signal, emitted from the target well, and noise obtained in the reference well. The obtained signal can be values of magnetic or electric fields or changes in said fields. The reconstructed reference signal, along with the obtained signal, is used to obtain a filtered probing signal. The position of the target well relative to the reference well can be determined based on the filtered probing signal. Position information can be used for directional drilling operations.
EFFECT: high accuracy of determining distance between a reference well and a target well, wider range in which a target well can be accurately detected, for planning or preventing wellbore intersection.
8 cl, 11 dwg
