An impact transmission mechanism for a rotary percussion drilling tool

Abstract

A tubular apparatus includes an upper joint, an inner cylinder, a piston, a metal seal, a bearing, and an anvil. The upper joint is connected to an outer cylinder. The inner cylinder has a cavity and is disposed within the outer cylinder. The piston has a piston rod disposed within the cavity of the inner cylinder and is moveable along an axis. The metal seal is disposed between the inner cylinder and a cylinder gland. The piston rod extends through the cylinder gland to a hammer, and a portion of the hammer is disposed within an outer tube. The bearing is disposed between the hammer and the outer tube. The anvil has a bit head and is connected to the hammer.

1 . A tubular apparatus comprising:
 an upper joint connected to an outer cylinder;   an inner cylinder, having a cavity, disposed within the outer cylinder;   a piston, having a piston rod, the piston disposed within the cavity of the inner cylinder and moveable along an axis;   a metal seal disposed between the inner cylinder and a cylinder gland, wherein the piston rod extends through the cylinder gland to a hammer and a portion of the hammer is disposed within an outer tube;   a bearing disposed between the hammer and the outer tube; and   an anvil, having a bit head, connected to the hammer.   
     
     
         2 . The tubular apparatus of  claim 1 , wherein the bearing further comprises a plurality of balls evenly spaced in at least one ring shape on an inner circumferential surface of the outer tube. 
     
     
         3 . The tubular apparatus of  claim 1 , wherein the bearing further comprises a shield ring disposed between the outer tube and the hammer. 
     
     
         4 . The tubular apparatus of  claim 3 , wherein the shield ring and the hammer define a lubricant cavity holding a lubricant. 
     
     
         5 . The tubular apparatus of  claim 3 , wherein the bearing further comprises a plurality of balls disposed along an inner circumferential surface of the shield ring. 
     
     
         6 . The tubular apparatus of  claim 1 , wherein the bearing further comprises at least one pillar mounted to the hammer. 
     
     
         7 . The tubular apparatus of  claim 6 , wherein the at least one pillar is disposed between the hammer and the outer tube. 
     
     
         8 . The tubular apparatus of  claim 6 , wherein the bearing further comprises a plurality of reinforcement blocks machined into the at least one pillar and an inner circumferential surface of the outer tube. 
     
     
         9 . The tubular apparatus of  claim 1 , further comprising an element gland having a central hole and a plurality of shunt holes disposed axially around the central hole. 
     
     
         10 . The tubular apparatus of  claim 9 , wherein the element gland is disposed within the outer cylinder and adjacent to a distal portion of the upper joint. 
     
     
         11 . The tubular apparatus of  claim 9 , further comprising a jet element disposed directly within the outer cylinder and located between the element gland and the inner cylinder. 
     
     
         12 . The tubular apparatus of  claim 11 , wherein the central hole and the plurality of shunt holes guide a fluid into the jet element to move the piston along the axis. 
     
     
         13 . The tubular apparatus of  claim 1 , further comprising a middle joint threaded into the outer cylinder and the outer tube. 
     
     
         14 . The tubular apparatus of  claim 13 , wherein a second portion of the hammer is disposed within the middle joint. 
     
     
         15 . The tubular apparatus of  claim 1 , further comprising an octagonal sleeve threaded into the outer tube. 
     
     
         16 . The tubular apparatus of  claim 15 , wherein the anvil further comprises a spiral ring groove configured to seal between the anvil and the octagonal sleeve. 
     
     
         17 . A method for extending a wellbore, the method comprising:
 providing a tubular apparatus comprising:
 an upper joint threaded into an outer cylinder; 
 an inner cylinder, having a cavity, disposed within the outer cylinder; 
 a piston, having a piston rod, the piston disposed within the cavity of the inner cylinder and moveable along an axis; 
 a metal seal disposed between the inner cylinder and a cylinder gland, wherein the piston rod extends through the cylinder gland to a hammer and a portion of the hammer is disposed within an outer tube; 
 a bearing disposed between the hammer and the outer tube; and 
 an anvil, having a bit head, connected to the hammer, and 
   running the tubular apparatus into the wellbore;   actuating the tubular apparatus to hammer the bit head against a bottom of the wellbore; and   breaking down the bottom of the wellbore to extend the wellbore.   
     
     
         18 . The method of  claim 17 , wherein actuating the tubular apparatus further comprises pumping a fluid along a flow path within the tubular apparatus. 
     
     
         19 . The method of  claim 18 , wherein pumping the fluid along the flow path further comprises driving the piston along the axis. 
     
     
         20 . The method  claim 19 , wherein pumping the fluid along the flow path further comprises creating a seal using a throttling effect of a fluid in a spiral ring groove.