Apparatus and method for controlling fluid flow in a rotary drill bit

Abstract

An apparatus for drilling a borehole in an earth formation is disclosed. The apparatus includes: an earth-boring rotary drill bit including a bit body having a plurality of cutters engagable with a subterranean earth formation; a fluid conduit disposed in the bit body, the fluid conduit being in fluid communication with a source of drilling fluid and configured to receive a portion of the drilling fluid; a nozzle extending between the fluid conduit and a surface of the bit body, the nozzle configured to apply a stream of the portion of the drilling fluid to a first location of the surface; and a valve assembly including an actuator and a valve, the actuator configured to move the valve and divert a flow path of the portion of the drilling fluid, thereby diverting at least part of the stream to a second location on the surface.

1 . An apparatus for drilling a borehole in an earth formation, the apparatus comprising:
 an earth-boring rotary drill bit including a bit body having a plurality of cutters engagable with a subterranean earth formation;   a fluid conduit disposed in the bit body, the fluid conduit being in fluid communication with a source of drilling fluid and configured to receive a portion of the drilling fluid;   a nozzle extending between the fluid conduit and a surface of the bit body, the nozzle configured to apply a stream of the portion of the drilling fluid to a first location of the surface; and   a valve assembly including an actuator and a valve, the actuator configured to move the valve and divert a flow path of the portion of the drilling fluid, thereby diverting at least part of the stream to a second location on the surface.   
   
   
       2 . The drill bit of  claim 1 , further comprising a processor configured to control at least one of rotation of the bit body and actuation of the valve assembly. 
   
   
       3 . The drill bit of  claim 1 , wherein the rotary drill bit is a polycrystalline diamond compact (“PDC”) drill bit. 
   
   
       4 . The drill bit of  claim 1 , wherein the bit body includes a plurality of blades, the first location is on at least one of the plurality of blades, and the second location is on at least another of the plurality of blades. 
   
   
       5 . The drill bit of  claim 1 , wherein diverting the at least part of the stream includes changing at least one of a direction, shape and pressure of the at least part of the stream. 
   
   
       6 . The drill bit of  claim 1 , wherein the valve is selected from at least one of a ball valve and a louver-type valve. 
   
   
       7 . The drill bit of  claim 1 , wherein the actuator is selected from at least one of a mechanical actuator, a piezoelectric actuator and a cam-type actuator. 
   
   
       8 . The drill bit of  claim 1 , further comprising a piston in operable connection with the actuator and the valve, wherein the valve is a piston head having a surface inclined relative to a central axis of at least a portion of the nozzle and the piston head is movable between a peripheral location and a central location of the nozzle. 
   
   
       9 . The drill bit of  claim 8 , wherein the valve includes at least one feature on the surface configured to direct a flow of the drilling fluid. 
   
   
       10 . The drill bit of  claim 1 , further comprising a biasing member fixedly connected to the bit body and to the valve, the biasing member configured to bias the valve toward a rest position. 
   
   
       11 . The drill bit of  claim 1 , wherein the valve is configured to move from a first position toward a second position in response to a change in a rotational rate of the bit body. 
   
   
       12 . The drill bit of  claim 11 , wherein the actuator includes a first member and a second member, the first tapered member having a first tapered portion in slidable contact with a second tapered portion of the second member, and the first tapered portion is tapered relative to a rotational axis of the bit body. 
   
   
       13 . The drill bit of  claim 1 , wherein the actuator includes a plurality of cams having at least two distinct cam profiles. 
   
   
       14 . A method of drilling a borehole in an earth formation, the method comprising:
 rotating a drill bit body including a plurality of cutters engagable with a subterranean earth formation;   pumping a drilling fluid into a fluid conduit disposed in the drill bit body;   receiving a portion of the drilling fluid in a nozzle extending between the fluid conduit and a surface of the drill bit body, and applying a stream of the portion of the drilling fluid from the nozzle to a first location of the surface; and   actuating a valve assembly in operable communication with the nozzle and diverting at least part of the stream from a first location to a second location.   
   
   
       15 . The method of  claim 14 , wherein actuating the valve assembly includes changing at least one of a fluid pressure and a rotational rate of the drill bit body. 
   
   
       16 . The method of  claim 14 , further comprising directing the portion of the drilling fluid away from the drill bit into an annular region between a drillstring and a wall of the borehole. 
   
   
       17 . The method of  claim 14 , wherein diverting the at least part of the stream includes changing at least one of a direction, shape and pressure of the at least part of the stream. 
   
   
       18 . The method of  claim 14 , wherein the valve assembly includes an actuator selected from at least one of a mechanical actuator, a piezoelectric actuator and a cam-type actuator. 
   
   
       19 . The method of  claim 18 , wherein the cam-type actuator includes at least one cam, and actuating the valve assembly includes rotating the cam between a first position and a second position. 
   
   
       20 . The method of  claim 14 , wherein the valve assembly includes a valve having a surface inclined relative to a central axis of at least a portion of the nozzle, and actuating the valve assembly includes moving the valve from a peripheral location toward a central location of the nozzle.