ADVANCED STEERING TOOL SYSTEM, METHOD AND APPARATUS

摘要

A steering tool is movable by a drill string to form an underground bore along an intended path. A sensing arrangement of the steering tool detects its pitch and yaw orientations at a series of spaced apart positions along the bore, each position is characterized by a measured extension of the drill string. The steering tool further includes a receiver. At least one marker is positioned proximate to the intended path, for transmitting a rotating dipole field to expose a portion of the intended path to the field for reception by the receiver. The detected pitch orientation, the detected yaw orientation and the measured extension of the drill string are used in conjunction with magnetic information from the receiver to locate the steering tool. The steering tool may automatically use the magnetic information when it is available. A customized overall position determination accuracy can be provided along the intended path.

主权项

1. An apparatus in a system including a steering tool that is moved by a drill string and steered in a way that is intended to form an underground bore along an intended path, beginning from a starting position, said apparatus comprising:
a steering tool including (i) a sensing arrangement for detecting a pitch orientation and a yaw orientation of the steering tool at each of a series of positions of the steering tool along said underground bore, each of which positions is characterized by a measured extension of said drill string such that each of the detected pitch orientation and yaw orientation are subject to a measurement error and (ii) a receiver, forming another part of the steering tool, configured for receiving a rotating dipole field that is receivable along a portion of the intended path to produce magnetic information along the portion of the intended path; and a processor that is configured to determine a first position of the steering tool, that is not exposed to the rotating dipole field, with a given accuracy based on the detected pitch orientation, the detected yaw orientation and a measured extension of the drill string, subject to the measurement error, and to determine a second position of the steering tool, that is exposed to the rotating dipole field, with an enhanced accuracy, based on the magnetic information in conjunction with the detected pitch orientation, the detected yaw orientation and the measured extension of the drill string to compensate for the accumulation of the measurement error along said portion of the intended path.