Rock bit with improved nozzle placement

Abstract

A rotary cone drill bit is provided with enhanced fluid flow near the bottom of an associated borehole resulting in improved removal of cuttings and other debris from the bottom of the borehole. The drill bit includes a plurality of fluid passageways extending from the bit body to the exterior of the drill bit. The bit body may include an enlarged cavity with the fluid passageways extending therefrom. One end of the cavity preferably includes an opening to receive fluid from a drill string attached to the drill bit. The end of the cavity opposite from the opening may have a generally parabolic configuration. For one application, a web member extends from the lower portion of the bit body, occupying a void area between each cutter cone assembly. The web member preferably contains a plurality of fluid passageways which direct drilling fluid from the drill string, through the bit body, through the web member, and exiting at nozzles adjacent to the bottom of the associated borehole.

What is claimed is:  
     
         1 . A rotary cone drill bit for forming a borehole, comprising: 
 a bit body having an upper portion adapted for connection to a drill string for rotation of the drill bit;    a number of support arms attached to the bit body and extending opposite from the upper portion, each of the support arms having a spindle connected thereto, each spindle projecting generally downwardly and inwardly with respect to its associated support arm;    a number of cutter cone assemblies equal to the number of support arms and mounted respectively on one of the spindles;    an enlarged cavity formed within the upper portion of the bit body for communicating fluids between the drill string and the cavity;    the bit body having a lower portion opposite from the upper portion;    more than four fluid passageways formed in the bit body extending between the cavity and the lower portion of the bit body; and    a nozzle disposed in each of the fluid passageways adjacent to the lower portion of the bit body.    
     
     
         2 . The drill bit as defined by    claim 1    wherein the lower portion of the bit body further comprises a generally convex exterior surface formed thereon.  
     
     
         3 . The drill bit as defined by    claim 1    wherein each fluid passageway further comprises: 
 an opening adjacent to the lower portion of the bit body; and  
 the respective opening having a threaded portion to receive the associated nozzle.  
 
     
     
         4 . The drill bit as defined by    claim 3    wherein the threaded portion of each fluid passageway is identical in size to the threaded portion of all other fluid passageways contained within the bit body.  
     
     
         5 . The drill bit as defined by    claim 3    wherein the threaded portion of at least one opening varies in size as compared to the threaded portion of the other openings.  
     
     
         6 . The drill bit as defined by    claim 1    further comprising: 
 the bit body having a longitudinal axis corresponding generally with a projected axis of rotation of the drill bit;  
 at least six fluid passageways extending through the bit body at a respective angle relative to the longitudinal axis of the bit body; and  
 at least one nozzle positioned to direct fluid flow between each cutter cone assembly and an adjacent cutter cone assembly.  
 
     
     
         7 . The drill bit as defined in    claim 1    wherein the cavity further comprises a generally uniform inside diameter extending from the opening to a position intermediate the bit body along a longitudinal axis of the bit body.  
     
     
         8 . The drill bit as defined in    claim 1    further comprising each nozzle having a respective outlet orifice of approximately the same size.  
     
     
         9 . The drill bit as defined in    claim 1    further comprising each nozzle having a respective outlet orifice and at least one nozzle having an outlet orifice larger than the outlet orifice of the other nozzles.  
     
     
         10 . The drill bit as defined by    claim 1    further comprising: 
 the bit body having a longitudinal axis corresponding generally with a projected axis of rotation for the drill bit;  
 first, second and third support arms attached to the bit body and extending therefrom with first, second and third cutter cone assemblies respectively mounted on the support arms;  
 the first and second support arms mounted on the exterior of the bit body spaced radially approximately one hundred ten degrees relative to each other;  
 the second and third support arms attached to the exterior of the bit body and spaced radially from each other approximately one hundred twenty degrees; and  
 the third support arm and the first support arm mounted on the exterior of the bit body and radially spaced approximately one hundred thirty degrees from each other on the exterior of the bit body.  
 
     
     
         11 . The drill bit as defined in    claim 1    further comprising: 
 the bit body having a longitudinal axis corresponding generally with a projected axis of rotation of the drill bit; and  
 at least one nozzle disposed adjacent to the longitudinal axis having a fluid flow rate which is substantially greater than the fluid flow rate through the other nozzles.  
 
     
     
         12 . The drill bit as defined in    claim 1    further comprising: 
 the bit body having a longitudinal axis corresponding generally with a projected axis of rotation of the drill bit; and  
 each of the nozzles spaced from the intersection of the longitudinal axis with the lower portion of the bit body whereby fluid flow from the nozzles is generally directed away from the axis of rotation of the drill bit.  
 
     
     
         13 . A rotary cone drill bit for forming a borehole, comprising: 
 a bit body having an upper portion adapted for connection to a drill string for rotation of the drill bit;    a number of support arms attached to the bit body and extending opposite from the upper portion;    a number of cutter cone assemblies equal to the number of support arms with each cutter cone assembly rotatably mounted on one of the support arms;    a void space formed between each cutter cone assembly and the cutter cone assembly disposed adjacent thereto;    a web member extending from a lower portion of the bit body and occupying the void space between each cutter cone assembly; and    a nozzle disposed in each fluid passageway adjacent to a lower portion of the web member.    
     
     
         14 . The drill bit of    claim 13    wherein the web member further comprises three blades with each blade disposed between adjacent cutter cone assemblies.  
     
     
         15 . The drill bit of    claim 13    further comprising at least one fluid passageway formed in the bit body and extending through the web member.  
     
     
         16 . A rotary cone drill bit for forming a borehole having a side wall and a bottom comprising: 
 a bit body having an upper portion with a threaded connection formed on the exterior of the upper portion for connecting the drill bit to a drill string for rotation of the drill bit;    a number of support arms attached to the bit body and extending opposite from the upper portion, each of the support arms having a spindle connected thereto, each spindle projecting generally downwardly and inwardly with respect to its associated support arm;    a number of cutter cone assemblies equal to the number of support arms with one of the cutter cone assemblies mounted respectively on each spindle for engagement with the side wall and bottom of the borehole;    the bit body having a longitudinal axis corresponding generally with a projected axis of rotation of the drill bit;    an enlarged cavity formed within the upper portion of the bit body for communicating fluids between the drill string and the cavity;    the enlarged cavity having a generally cylindrical configuration disposed along the longitudinal axis;    the bit body having a lower portion opposite from the upper portion; and    at least six fluid passageways formed in the bit body extending between the cavity and the lower portion of the bit body.    
     
     
         17 . The drill bit of    claim 16    further comprising: 
 at least six of the fluid passageways extending through the bit body at an angle relative to the longitudinal axis of the bit body;  
 at least one additional fluid passageway extending from the cavity along the longitudinal axis to the lower portion of the bit body; and  
 a nozzle positioned in each fluid passageway to direct fluid flow toward the bottom of the borehole;  
 
     
     
         18 . The drill bit of    claim 16    further comprising: 
 one of the nozzles located a first distance (R 1 ) away from the intersection of the lower portion of the bit body and the longitudinal axis, with a first inside diameter (d 1 );  
 one of the nozzles located a second distance (R 2 ) away from the intersection of the member and the longitudinal axis, with a second inside diameter (d 2 );  
 the distance (R 2 ) greater than the distance (R 1 ); and  
 the inside diameter (d 2 ) larger than the inside diameter (d 1 ) creating a drilling fluid flow away from the longitudinal axis along the bottom of the borehole.  
 
     
     
         19 . A rotary cone drill bit for forming a borehole comprising: 
 a bit body having an upper portion adapted for connection to a drill string for rotation of the drill bit;    a number of support arms attached to the bit body and extending therefrom;    a number of cutter cone assemblies equal to the number of support arms with each cutter cone assembly rotatably mounted on one of the support arms;    an enlarged cavity formed within the upper portion of the bit body;    the cavity having a first end defined in part by an opening for communicating fluids between the drill string and the cavity;    the cavity having a second end disposed within the bit body;    the second end of the cavity having a generally parabolic configuration;    a number of fluid passageways formed in the bit body extending between the second end of the cavity and a lower portion of the bit body; and    a nozzle disposed in each of the fluid passageways adjacent to the lower portion of the bit body.    
     
     
         20 . A rotary cone drill bit for forming a borehole comprising: 
 a bit body having an upper portion adapted for connection to a drill string for rotation of the drill bit;    a number of support arms attached to the bit body and extending therefrom;    a number of cutter cone assemblies equal to the number of support arms with each cutter cone assembly rotatably mounted on one of the support arms;    an enlarged cavity formed within the upper portion of a bit body;    the enlarged cavity having a first end defined in part by an opening in the upper portion of the bit body for communicating drilling fluids between the drill string and the cavity;    the enlarged cavity having a second end disposed within the bit body;    the bit body having a longitudinal axis corresponding generally with a projected axis of rotation of the drill bit;    a first fluid passageway formed in the bit body and extending from the second end of the cavity to a position spaced from a lower portion of the bit body; and    at least two additional fluid passageways formed in the bit body extending through the lower portion of the bit body and intersecting the first fluid passageway.    
     
     
         21 . The drill bit of    claim 20    further comprising: 
 the first fluid passageway extending along the longitudinal axis of the bit body; and  
 three additional fluid passageways extending through the lower portion of the bit body and intersecting the first fluid passageway.  
 
     
     
         22 . A rotary cone drill bit for forming a borehole comprising: 
 a bit body having an upper portion adapted for connection to a drill string for rotation of the drill bits;    first, second and third support arms attached to the exterior of the bit body and extending therefrom;    a respective cutter cone assembly rotatably mounted on each of the support arms;    the bit body having a longitudinal axis corresponding generally with a projected axis of rotation of the drill bit;    the first support arm and the second support arm spaced radially a first number of degrees from each other on the exterior of the bit body;    the second support arm and the third support spaced radially a second number of degrees from each other on the exterior of the bit body;    the third support arm spaced radially from the first support arm at a third number of degrees; and    the first number of degrees plus the second number of degrees plus the third number of degrees equal to three hundred sixty degrees.    
     
     
         23 . The drill bit of    claim 22    further comprising: 
 the first number of degrees approximately equal to one hundred ten;  
 the second number of degrees approximately equal to one hundred twenty; and  
 the third number of degrees approximately equal to one hundred thirty.  
 
     
     
         24 . A rotary cone drill bit for forming a borehole comprising: 
 a bit body having an upper portion adapted for connection to a drill string for rotation of the drill bit;    the bit body having a longitudinal axis corresponding generally with a projected axis of rotation for the drill bit;    a number of support arms attached to the bit body and extending therefrom;    a number of cutter cone assemblies equal to the number of support arms with each cutter cone assembly rotatably mounted on one of the support arms;    an enlarged cavity formed within the upper portion of the bit body;    the cavity having a first end defined in part by an opening for communicating fluids between the drill string and the cavity;    the cavity having a second end disposed within the bit body;    the second end of the cavity having a generally parabolic configuration;    a number of fluid passageways formed in the bit body extending between the second end of the cavity and a lower portion of the bit body; and    at least one of the fluid passageways having a generally curved configuration relative to the longitudinal axis.    
     
     
         25 . The drill bit of    claim 24    further comprising a nozzle disposed in each of the fluid passageways adjacent to the lower portion of the bit body.