Downhole drilling assembly having a hydraulically actuated clutch and method for use of same

A downhole drilling assembly comprising:

• a drill string having an inner fluid passageway;
• a fluid motor disposed within the drill string, the fluid motor having a stator and a rotor, the rotor operable to rotate relative to the stator in response to a circulating fluid received via the inner fluid passageway of the drill string;
• a drive shaft operably associated with the rotor, the drive shaft rotating responsive to rotation of the rotor;
• a drill bit operably associated with the drive shaft, the drill bit rotating responsive to rotation of the drive shaft;
• and
• a hydraulically actuated clutch disposed within the drill string, the clutch having a swash plate pump, a first clutch assembly operable to rotate with the drill string and a second clutch assembly operable to rotate with the drive shaft,
• wherein, in a first configuration, the first clutch assembly is disengaged from the second clutch assembly such that rotation of the rotor relative to the stator causes the drive shaft and the drill bit to rotate relative to the drill string;
• and
• wherein, in a second configuration, the swash plate pump generates hydraulic pressure via rotation of the drill string relative to the drive shaft, which hydraulic pressure engages the first clutch assembly with the second clutch assembly such that the drive shaft and the drill bit rotate together with the drill string.

A method of operating a downhole drilling assembly comprising:

• disposing a drill string having an inner fluid passageway and a downhole drilling motor assembly in a wellbore;
• pumping a circulating fluid through the inner fluid passageway and the downhole drilling motor assembly;
• rotating a rotor of the downhole drilling motor assembly relative to a stator of the downhole drilling motor assembly responsive to the circulating fluid;
• rotating a drive shaft responsive to the rotation of the rotor;
• rotating a drill bit relative to the drill string responsive to the rotation of the drive shaft;
• rotating the drill string relative to the drive shaft;
• generating hydraulic pressure with a pump, via the rotation of the drill string relative to the drive shaft, to engage a hydraulically actuated clutch;
• and
• rotating the drill bit together with the drill string responsive to the engagement of the hydraulically actuated clutch.