A system includes a surface coil positioned at a known surface position, the surface coil including at least one loop of a conductor. The system also includes a coil controller coupled to the surface coil and adapted to inject a current into the surface coil such that the surface coil generates an electromagnetic field. In addition, the system includes a sensor package positioned within a wellbore adapted to detect the electromagnetic field and determine the position of the wellbore relative to the surface coil.

A system includes a surface coil positioned at a known surface position, the surface coil including at least one loop of a conductor. The system also includes a coil controller coupled to the surface coil and adapted to inject a current into the surface coil such that the surface coil generates an electromagnetic field. In addition, the system includes a sensor package positioned within a wellbore adapted to detect the electromagnetic field and determine the position of the wellbore relative to the surface coil.

A tracking system for communicating a location of a beacon in order to drill a bore path. The beacon is carried by a drill string in a drilling operation. Above-ground trackers are arranged in a path to define an intended underground bore path. The trackers form a multi-node mesh network in communication with a display unit at a drilling rig. A drilling operator guides the drill string in response to tracking data sent from the tracking system.

A tracking system for communicating a location of a beacon in order to drill a bore path. The beacon is carried by a drill string in a drilling operation. Above-ground trackers are arranged in a path to define an intended underground bore path. The trackers form a multi-node mesh network in communication with a display unit at a drilling rig. A drilling operator guides the drill string in response to tracking data sent from the tracking system.

An apparatus and method of determining position of a drilling tool during drilling is disclosed. The apparatus includes a magnetic source mounted to a rotating drilling tool and at least three magnetometers, which are located outside a drilled hole. Sensing data of the rotating magnetic field is transmitted from the magnetometers to a control unit (CU) provided with a position calculation algorithm. The control unit is also provided with pose data of the magnetometers. The control unit compares the received sensing data and determines phase angles from the sensing data. The algorithm utilizes the phase angles and the known positions of the magnetometers when calculating the position.

An apparatus and method of determining the position of a drilling tool during drilling is provided. The apparatus includes a magnetic source mounted to a rotating drilling tool and at least two magnetometers, which are located outside a drilled hole. Sensing data of a rotating magnetic field is transmitted from the magnetometers to a control unit provided with a position calculation algorithm. The control unit is also provided with position data of the magnetometers and a reference position of the drilling tool. The control unit compares the received sensing data when the drilling tool is in the reference position and when being moved to a new position. Phase angles are then detected from the sensing data. The algorithm utilizes the phase angles and the known positions of the magnetometers and the reference point when calculating the changed position.

A device rotates at least one static magnetic field about an axis, producing a rotating magnetic dipole field, and is movable in relation to the surface of the ground. The field is periodically sensed using a receiver to produce a receiver output responsive to the field. A positional relationship between the receiver and the device is monitored using the output. In one aspect, changing the positional relationship, by moving the device nearer to a boring tool which supports the receiver, causes an increase in accuracy of depth determination. In another aspect, determination of an actual overhead position of the boring tool, and its application, are described. Use of a plurality of measurements over at least one-half revolution of each magnet is disclosed. Establishing a surface radial direction toward a boring tool and resolution of multi-valued parameters is described. Calibration techniques, as well as a three transmitter configuration are also described.

A device rotates at least one static magnetic field about an axis, producing a rotating magnetic dipole field, and is movable in relation to the surface of the ground. The field is periodically sensed using a receiver to produce a receiver output responsive to the field. A positional relationship between the receiver and the device is monitored using the output. In one aspect, changing the positional relationship, by moving the device nearer to a boring tool which supports the receiver, causes an increase in accuracy of depth determination. In another aspect, determination of an actual overhead position of the boring tool, and its application, are described. Use of a plurality of measurements over at least one-half revolution of each magnet is disclosed. Establishing a surface radial direction toward a boring tool and resolution of multi-valued parameters is described. Calibration techniques, as well as a three transmitter configuration are also described.

A system includes a receiver component that receives a model of a well system, the model comprising a representation of an electrically energized well casing and/or a fracture as a transmission line that leaks electric current as the current traverses the well casing and/or fracture. The receiver component also receives a value that indicates an amount of the current that is applied to the well casing and a location of a source of the current on the well casing. The system further includes an electromagnetic field calculator component that calculates an estimated electromagnetic field at at least one location on the surface of the earth based at least in part upon the representation of the electrically energized well casing and/or fracture, the value that indicates the amount of current that is applied to the well casing, and the location of the source of the current on the well casing.

A beacon assembly located at a downhole end of a drill string proximate a boring tool. The beacon assembly transmits data to an above-ground receiver. The beacon has a housing with a housing wall located between its sensors, such as gradiometers, accelerometers, and other orientation sensors, and an antenna assembly. The antenna assembly has a protective covering made of electromagnetically transparent material.