A pressure generating device for use in downhole drilling operations includes a rotating valve portion having a first body with at least one first flow channel, and a stationary valve portion having a second body with at least one second flow channels and at least one bypass channel. A flow restrictor is positioned within the at least one bypass channel for adjusting a total flow area of the at least one bypass channel. During rotation of the rotating valve portion relative to the stationary valve portion, a total flow area of a passage defined by the first flow channel(s), the second flow channel(s), and the at least one bypass channel varies according to a uniform closure pattern to provide uniform pressure pulses within a single revolution of the rotating valve portion. A method of generating uniform pressure pulses in downhole drilling operations is also disclosed.

A pressure generating device for use in downhole drilling operations includes a rotating valve portion having a first body with at least one first flow channel, and a stationary valve portion having a second body with at least one second flow channels and at least one bypass channel. A flow restrictor is positioned within the at least one bypass channel for adjusting a total flow area of the at least one bypass channel. During rotation of the rotating valve portion relative to the stationary valve portion, a total flow area of a passage defined by the first flow channel(s), the second flow channel(s), and the at least one bypass channel varies according to a uniform closure pattern to provide uniform pressure pulses within a single revolution of the rotating valve portion. A method of generating uniform pressure pulses in downhole drilling operations is also disclosed.

A flushing system in a drill bit is disclosed. The drill bit includes a body that defines the flushing system. The flushing system includes an inlet to facilitate supply of pressurized fluids into the bore hole. A cutting surface of the drill bit is provided with a main opening that defines a main passageway in communication with the inlet. A peripheral surface of the drill bit is provided with a secondary opening that defines a secondary passageway in communication with the inlet. The secondary passageway is disposed at an angle from a horizontal reference plane. The horizontal reference plane is defined between the inlet and the origin of the main passageway and is perpendicular to a central longitudinal axis of the body of the drill bit. An origin of the secondary passageway is at a distance from the origin of main passageway.

A flushing system in a drill bit is disclosed. The drill bit includes a body that defines the flushing system. The flushing system includes an inlet to facilitate supply of pressurized fluids into the bore hole. A cutting surface of the drill bit is provided with a main opening that defines a main passageway in communication with the inlet. A peripheral surface of the drill bit is provided with a secondary opening that defines a secondary passageway in communication with the inlet. The secondary passageway is disposed at an angle from a horizontal reference plane. The horizontal reference plane is defined between the inlet and the origin of the main passageway and is perpendicular to a central longitudinal axis of the body of the drill bit. An origin of the secondary passageway is at a distance from the origin of main passageway.

A drill bit nozzle includes a nozzle body, a channel in the nozzle body, and a nozzle outlet arranged at an end of the nozzle body and in communication with the channel. The nozzle outlet is a strip-shaped outlet configured to eject a sheet-like jet flow. Since the nozzle outlet of the drill bit nozzle is a strip-shaped outlet, the nozzle outlet is able to eject a sheet-like jet flow. When the drill bit nozzle is applied to a PDC drill bit, the drill bit nozzle can uniformly eject a drilling fluid onto each cutting tooth, which ensures that the cutting teeth in the drill bit may obtain good cooling and chip removal effects, while avoiding excessive concentration of the jet flow from the drill bit nozzle which may erode the cutting teeth, thereby prolonging the service life of the drill bit.

A drill bit nozzle includes a nozzle body, a channel in the nozzle body, and a nozzle outlet arranged at an end of the nozzle body and in communication with the channel. The nozzle outlet is a strip-shaped outlet configured to eject a sheet-like jet flow. Since the nozzle outlet of the drill bit nozzle is a strip-shaped outlet, the nozzle outlet is able to eject a sheet-like jet flow. When the drill bit nozzle is applied to a PDC drill bit, the drill bit nozzle can uniformly eject a drilling fluid onto each cutting tooth, which ensures that the cutting teeth in the drill bit may obtain good cooling and chip removal effects, while avoiding excessive concentration of the jet flow from the drill bit nozzle which may erode the cutting teeth, thereby prolonging the service life of the drill bit.

An example drill bit includes a body that is connectable to a drill string. The body has a base configured to face downhole within a wellbore and a perimeter configured to face a wall of the wellbore. The body includes a first nozzle and a second nozzle. The first nozzle corresponds to a first channel that exits the body through the perimeter and the second nozzle corresponds to a second channel that exits the body through the base. The example drill bit also includes a bit cutter on the base of the body and a valve within the body. The valve is configured to move within the body to block either the first channel or the second channel.

An example drill bit includes a body that is connectable to a drill string. The body has a base configured to face downhole within a wellbore and a perimeter configured to face a wall of the wellbore. The body includes a first nozzle and a second nozzle. The first nozzle corresponds to a first channel that exits the body through the perimeter and the second nozzle corresponds to a second channel that exits the body through the base. The example drill bit also includes a bit cutter on the base of the body and a valve within the body. The valve is configured to move within the body to block either the first channel or the second channel.

A drill bit nozzle assembly and drill bit including the same may include a conical or frustum contoured nozzle body. The nozzle body includes multiple movable closure elements circumferentially arranged to form an inlet orifice, a variable diameter outlet orifice, and a fluid a passage to transport fluid from the inlet orifice to the variable diameter outlet orifice. The nozzle assembly may further include an actuator configured to vary a diameter of the variable diameter outlet orifice based on a change of position of the movable closure elements.

A drill bit nozzle assembly and drill bit including the same may include a conical or frustum contoured nozzle body. The nozzle body includes multiple movable closure elements circumferentially arranged to form an inlet orifice, a variable diameter outlet orifice, and a fluid a passage to transport fluid from the inlet orifice to the variable diameter outlet orifice. The nozzle assembly may further include an actuator configured to vary a diameter of the variable diameter outlet orifice based on a change of position of the movable closure elements.