Determining beacon location using magnetic field shape measurements

摘要

A method and system for identifying a location of a magnetic field source. A total magnetic field is measured during a calibration routine prior to a drilling procedure. During the drilling procedure, a magnetic field measurement is obtained. Using the measured magnetic field and the calibrated field, a set of possible angles and distances is calculated. After the source is advanced a known distance, a second magnetic field measurement is obtained. A second set of possible angles and distances is calculated. The relative location of the source is then determined using the first set and second set of values, along with the known distance and a pitch angle of the source.

主权项

1. A method for determining the location of a beacon comprising a source of a magnetic field, the method comprising:
obtaining a reference measurement of a magnetic field from the source; detecting the magnetic field from the source when the beacon is at an unknown first location to determine a first measurement; advancing the beacon a known distance to an unknown second location; detecting the magnetic field from the source when the beacon is at the unknown second location to determine a second measurement; determining an orientation of the beacon; and determining the second location of the source from a shape of the detected magnetic field using the first and second measurements, the known distance, the reference measurement, and the orientation.