A technique facilitates drilling applications by providing a unique flex joint. In one embodiment, the flex joint has an adjustable bending stiffness while being much more compact than conventional flex joints. The flex joint also may be designed to de-couple bending moments from the tool joints and, in some applications, can operate as an active vibration and shock control sub by incorporating suitable sensors and a hydraulic actuator system. The design also enables incorporation of other features, such as electrical insulation features disposed above and/or below the flex joint. In some applications, the flex joint also may have an electrical feed through.

A method for wellbore directional drilling includes selecting a starting and stopping spatial position of at least one portion of the wellbore. A sequence of sliding and rotary drilling operations within the portion is determined to calculate a wellbore trajectory. The sequence has at least one drilling operating parameter. The operations include a constraint on the drilling operating parameter or the calculated trajectory. The calculated trajectory includes a projected steering response of a steerable motor in response to the at least one drilling operating parameter. Drilling the portion of the wellbore is started. A spatial position of the wellbore during drilling is determined at at least one point intermediate the starting and stopping positions. Using a relationship between the projected steering response and the drilling operating parameter, the drilling parameter and/or the constraint are adjusted based on the measured spatial position and the stopping spatial position.

In accordance with some embodiments of the present disclosure, systems and methods for a gain scheduling based toolface control system for a rotary steerable drilling tool are disclosed. The method includes determining a desired toolface of a drilling tool, calculating a toolface error by determining a difference between a current toolface and the desired toolface, determining a plurality of operating points of the drilling tool, selecting one of the plurality of operating points based on a current operating point of the drilling tool, determining a model based on the selection, calculating a correction to correct the toolface error, the correction based on the model, transmitting a signal to the drilling tool such that the signal adjusts the current toolface based on the correction, and drilling a wellbore with a drill bit oriented at the desired toolface.

In accordance with some embodiments of the present disclosure, systems and methods for a feedback based toolface control system for a rotary steerable drilling tool is disclosed. The method includes determining a desired toolface of a drilling tool, calculating a toolface error, calculating a correction to correct the toolface error by: estimating, using a model, an output of each of a plurality of states of the model based on an input to each of the states of the model and determining a desired input to each of the plurality of states, beginning at the toolface, based on a desired output of at least one of the plurality of states connected to a particular state, transmitting the signal to the input component of the drilling tool such that the signal adjusts the current toolface based on the correction, and drilling a wellbore with a drill bit oriented at the desired toolface.

A motor rotary steerable system having a sun gear shaft, a pair of planetary gears rotated by the sun gear shaft, an adjustable slip clutch assembly rotated by the planetary gears in an opposite direction, and an orienting device connected to the planetary gears and adjustable slip clutch assembly. The orienting device comprises a bent sub with a bent sub housing, a bearing section, a bit drive assembly, a pulse counter to count the rotating drive shaft rotations, a drilling bit locator, and a transmitting device conveying signals from the orienting device to a receiver in an opposite side of a power section. The orienting device rotates independently from a drill string and is synchronously timed to the rotation of the drill string to rotate continuously while producing both straight and curved bore path segments and increase production rates.

Systems including a plurality of sensors disposed on a bottom hole assembly (BHA) configured to provide data to a controller, wherein a drill bit is connected to a bottom of the BHA; and a controller configured to: receive a well plan; receive, at a first stationary survey station, locational data and directional data of the BHA from the plurality of sensors; create steering instructions based on the well plan, historical drilling data, and the locational and directional data; generate a predicted future position of the drill bit for each of a plurality of stationary survey stations subsequent to the first stationary survey station assuming implementation of the steering instructions; display the predicted future position of the drill bit for each stationary survey station on a graphical user interface; receive directions to implement, reject, or revise the steering instructions; and execute the received directions. Methods and machine-readable media are also included.

A drilling assembly includes a straight housing in which a mud motor assembly is mounted. The mud motor includes a rotor that rotates within a stator. The rotor has an axial centerline substantially parallel with the housing. A drivetrain is coupled between the rotor and a driveshaft. The driveshaft is coupled to a drill head. The driveshaft has a centerline that is non-coincident with (i.e., offset or angled) the axial centerline. The angle between the driveshaft centerline and the axial centerline may be fixed or variable. The angle may be variable in response to an axial force, imparted to the rotor, that is transferred to the driveshaft through the drivetrain. Additional apparatus, systems, and methods are disclosed.

This disclosure provides a downhole drilling tool that has a deep-reading logging tool, a near-bit resistivity tool, and a gamma ray detector. Formation information logged using the deep-reading logging tool is used to build a preliminary stratigraphic model with a relatively low resolution. The preliminary stratigraphic model is further refined using data logged using the near-bit resistivity tool and/or the gamma ray detector to obtain a refined stratigraphic model with a higher resolution. The model is used to guide geosteering to achieve better well placement and trajectory control.

A method for drilling a wellbore includes rotating a drill string having a steerable drilling motor proximate a distal end thereof in a wellbore to a selected tool face angle. A torque applied to the drill string and a rotational orientation of the drill string is measured at spaced apart positions along the drill string. The drill string is rotated in a first direction until rotation at one of the selected positions is measured. Rotation of the drill string is reversed to a second direction until rotation of the drill string at the one of the selected positions is measured. Rotation of the drill string is reversed to the first direction until a torque measured at at least one position along the drill string corresponds to a torque measured when drill string rotation was reversed from the first direction.

A steerable well bore drilling device and method are disclosed. The steerable well bore drilling device comprises a drill string, a bit coupled to the drill string, a drilling motor within the drill string and driving the bit, and a pair of eccentric reamers coupled to the drill string and positioned between the bit and the motor.