A sensor is configured to sense a deflection angle and to transmit a second signal representing the sensed deflection angle to a downhole control unit. The downhole control unit is configured receive signals from at least the sensor. An adjustable bent sub assembly is mechanically coupled to the power section. The adjustable bent sub assembly is configured to, while the downhole motor is in the wellbore, adjust the deflection angle to the desired deflection angle. A biasing mechanism is communicatively coupled to the downhole control unit and mechanically coupled to the adjustable bent sub assembly. The biasing mechanism is configured to, while the downhole motor is in the wellbore, actuate the adjustable bent sub assembly responsive to the downhole control unit. A locking mechanism is coupled to the adjustable bent sub assembly. The locking mechanism is configured to lock the desired deflection angle.

A sensor is configured to sense a deflection angle and to transmit a second signal representing the sensed deflection angle to a downhole control unit. The downhole control unit is configured receive signals from at least the sensor. An adjustable bent sub assembly is mechanically coupled to the power section. The adjustable bent sub assembly is configured to, while the downhole motor is in the wellbore, adjust the deflection angle to the desired deflection angle. A biasing mechanism is communicatively coupled to the downhole control unit and mechanically coupled to the adjustable bent sub assembly. The biasing mechanism is configured to, while the downhole motor is in the wellbore, actuate the adjustable bent sub assembly responsive to the downhole control unit. A locking mechanism is coupled to the adjustable bent sub assembly. The locking mechanism is configured to lock the desired deflection angle.

The disclosed embodiments include a system, method, or computer-program product configured to performing automated wellbore trajectory control for correcting between an actual wellbore trajectory path and a planned wellbore trajectory path. For example, in one embodiment, a controller is configured to obtain real-time data gathered during the drilling operation, determine whether the actual wellbore trajectory path deviates from the planned wellbore trajectory path, and automatically initiate the wellbore trajectory control to change the actual wellbore trajectory path to a minimum-incremental wellbore energy correction path using provided correction constraints. The correction path may optionally include spline, catenary, circular arc, or clothoid curves.

There is provided herein a system and method for automatically determining a path within a target rock unit of a directionally drilled well (a target well) using log readings, e.g., gamma log readings, taken in the target well as compared with log readings (a typelog) taken in a well that penetrates the target rock unit (an offset well). Most specifically, in some embodiments the path of the target well within the target rock unit will be obtained by solving a minimum travel distance problem which uses distances that are based on differences between well log readings in the target and offset wells. Solution of this problem will yield a collection of stratigraphic blocks lengths and dips that define a path of a well in a subsurface through the target formation or rock unit.

Systems and methods for determining azimuth of a wellbore while drilling. A method of drilling a wellbore that includes rotating a drill bit to extend the wellbore into a subterranean formation. The method may further include measuring magnetic toolface with a first magnetometer while rotating the drill bit. The method may further include obtaining a cross-axial magnetic field measurement. The method may further include determining azimuth at a point in the wellbore using at least the magnetic toolface and the cross-axial magnetic field measurement. The method may further include using the azimuth as feedback in the drilling the wellbore.

A boring tool moves having a pitch orientation, a yaw orientation and a roll orientation and is steerable underground using the roll orientation. A maximum drill string curvature is established for steering. The boring tool is advanced over a path segment. An averaged roll characteristic is determined for movement of the boring tool along the path segment. A path segment pitch orientation is established based on at least one measured pitch orientation along the path segment. Using the maximum drill string curvature in combination with the averaged roll characteristic and the path segment pitch orientation, the yaw orientation is determined. The averaged roll characteristic is determined based on a series of incremental roll measurements that are spaced across the path segment. A set of coupled ordinary differential equations is used to characterize movement of the boring tool.

A boring tool moves having a pitch orientation, a yaw orientation and a roll orientation and is steerable underground using the roll orientation. A maximum drill string curvature is established for steering. The boring tool is advanced over a path segment. An averaged roll characteristic is determined for movement of the boring tool along the path segment. A path segment pitch orientation is established based on at least one measured pitch orientation along the path segment. Using the maximum drill string curvature in combination with the averaged roll characteristic and the path segment pitch orientation, the yaw orientation is determined. The averaged roll characteristic is determined based on a series of incremental roll measurements that are spaced across the path segment. A set of coupled ordinary differential equations is used to characterize movement of the boring tool.

Systems and methods for determining azimuth of a wellbore while drilling. A method of drilling a wellbore that includes rotating a drill bit to extend the wellbore into a subterranean formation. The method may further include measuring magnetic toolface with a first magnetometer while rotating the drill bit. The method may further include obtaining a cross-axial magnetic field measurement. The method may further include determining azimuth at a point in the wellbore using at least the magnetic toolface and the cross-axial magnetic field measurement. The method may further include using the azimuth as feedback in the drilling the wellbore.

Systems, apparatus and methods are described for purposes of initiating a response to detection of an adverse operational condition involving a system including a drill rig and an inground tool. The response can be based on an uphole sensed parameter in combination with a downhole sensed parameter. The adverse operational condition can involve cross-bore detection, frac-out detection, excessive downhole pressure, a plugged jet indication and drill string key-holing detection. A communication system includes an inground communication link that allows bidirectional communication between a walkover detector and the drill rig via the inground tool. Monitoring of inground tool depth and/or lateral movement can be performed using techniques that approach integrated values. Bit force based auto-carving is described in the context of an automated procedure.

A sensor is configured to sense a deflection angle and to transmit a second signal representing the sensed deflection angle to a downhole control unit. The downhole control unit is configured receive signals from at least the sensor. An adjustable bent sub assembly is mechanically coupled to the power section. The adjustable bent sub assembly is configured to, while the downhole motor is in the wellbore, adjust the deflection angle to the desired deflection angle. A biasing mechanism is communicatively coupled to the downhole control unit and mechanically coupled to the adjustable bent sub assembly. The biasing mechanism is configured to, while the downhole motor is in the wellbore, actuate the adjustable bent sub assembly responsive to the downhole control unit. A locking mechanism is coupled to the adjustable bent sub assembly. The locking mechanism is configured to lock the desired deflection angle.