RANGE POSITIONING TOOL FOR USE WITHIN A CASING OR LINER STRING

摘要

A method for detecting a downhole position in a wellbore comprises: providing a set of signal emitters, each signal emitter in the set attached to a different position in the wellbore and each signal emitter configured to emit a signal having a unique characteristic; and providing a measurement tool comprising a signal detector configured to detect the different signals and a rotation device configured to rotatably contact a wall of the wellbore. The measurement tool is moved through the wellbore and one or more positions of the measurement tool in the wellbore is determined by detecting one or more of the signals and identifying the position of one or more of the signal emitters by the unique characteristic of each detected signal, and by detecting the number of rotations in a ranging wheel of the rotation detector that contacts the wellbore.