Rotating Magnet Ranging (RMR) employs a permanent magnet in a sub directly behind the drillbit to generate a time varying magnetic field as the bit rotates. This signal is detected by sensors in a nearby well. RMR has been tested in SAGD projects and shown to be capable of correctly positioning new injectors above previously drilled and cased production wells. In these applications, the sensor package is pumped down tubing installed in the producer. The current bit location is evaluated relative to the sensor package along with an estimate of the relative drilling direction. RMR is being used routinely to guide horizontal wells to intersect vertical wells. In this application, the sensor is deployed on a wireline in an uncased interval of the vertical well near the proposed intersection depth. RMR provides steering information to the driller up to 50 meters from the target.

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