Steerable bit system assembly and methods

A method for drilling a wellbore in an earthen formation,

• comprising:
• conveying a drill string into the wellbore, the drill string having a bottomhole assembly (BHA) coupled to an end thereof, the BHA including a drill bit;
• and
• steering the BHA with a steering unit positioned along the drill string and including:
• (i) a control element containing a member at least partially formed of a shape changing smart material, wherein a shape change of the smart material in response to an excitation signal applies a force to the control element to cause the control element to apply a force on a wellbore wall;
• and (ii) providing the excitation signal to the control element.

A method for drilling a wellbore in an earthen formation,

• comprising:
• conveying a drill string into the wellbore, the drill string having a bottomhole assembly (BHA) coupled to an end thereof, the BHA including a drill bit;
• and
• steering the BHA with a rotating steering unit including:
• (i) a control element containing a member at least partially formed of a shape changing smart material, wherein a shape change of the smart material in response to an excitation signal applies a force to the control element to apply a side force to a wellbore wall;
• and (ii) providing the excitation signal by a control unit to the control element, wherein the drill bit includes a force pad and a gage cutter each of which includes an associated control element;
• and
• selectively engaging the wellbore wall with the force pad and gage cutter in response to the excitation signal provided by the control unit to the associated control element.