Coiled tubing percussion drilling

Abstract

A method of drilling a subterranean wellbore can include extending coiled tubing into the wellbore, and actuating an impact tool interconnected to the coiled tubing, thereby delivering impacts to a drill bit. A coiled tubing drilling system for drilling a subterranean wellbore can include coiled tubing, a drill bit, and an impact tool which delivers impacts to the drill bit.

1 . A method of drilling a subterranean wellbore, the method comprising:
 extending coiled tubing into the wellbore; and   actuating an impact tool interconnected to the coiled tubing, thereby delivering impacts to a drill bit.   
     
     
         2 . The method of  claim 1 , wherein the impact tool comprises a fluid hammer. 
     
     
         3 . The method of  claim 1 , wherein the impact tool comprises a pneumatic hammer. 
     
     
         4 . The method of  claim 1 , further comprising interconnecting a shock absorber between the coiled tubing and the impact tool. 
     
     
         5 . The method of  claim 1 , wherein actuating the impact tool further comprises pumping a liquid through the coiled tubing to the impact tool. 
     
     
         6 . The method of  claim 1 , wherein actuating the impact tool further comprises pumping a gas through the coiled tubing to the impact tool. 
     
     
         7 . The method of  claim 6 , wherein the gas comprises nitrogen. 
     
     
         8 . The method of  claim 6 , wherein the gas is substantially free of oxygen. 
     
     
         9 . The method of  claim 6 , wherein actuating the impact tool further comprises pumping, along with the gas, additional one or more components selected from a lubricant, a friction reducer, a foam, oil, a mist, drilling mud, and water. 
     
     
         10 . The method of  claim 1 , further comprising rotating the drill bit while actuating the impact tool. 
     
     
         11 . The method of  claim 10 , wherein rotating the drill bit further comprises operating a positive displacement motor which rotates the drill bit in response to fluid flow through the coiled tubing. 
     
     
         12 . The method of  claim 10 , wherein rotating the drill bit further comprises operating a turbine which rotates the drill bit in response to fluid flow through the coiled tubing. 
     
     
         13 . The method of  claim 1 , wherein actuating the impact tool is performed while the drill bit is not rotated by a motor. 
     
     
         14 . The method of  claim 1 , wherein actuating the impact tool further comprises pumping a compressible fluid through the coiled tubing to the impact tool. 
     
     
         15 . The method of  claim 1 , wherein actuating the impact tool further comprises pumping an incompressible fluid through the coiled tubing to the impact tool. 
     
     
         16 . A coiled tubing drilling system for drilling a subterranean wellbore, the system comprising:
 coiled tubing;   a drill bit; and   an impact tool which delivers impacts to the drill bit.   
     
     
         17 . The system of  claim 16 , wherein the drill bit rotates while the impact tool delivers the impacts to the drill bit. 
     
     
         18 . The system of  claim 16 , further comprising a positive displacement motor which rotates the drill bit in response to fluid flow through the coiled tubing. 
     
     
         19 . The system of  claim 16 , further comprising a turbine which rotates the drill bit in response to fluid flow through the coiled tubing. 
     
     
         20 . The system of  claim 16 , wherein the impact tool delivers the impacts to the drill bit while the drill bit is not rotated by a motor. 
     
     
         21 . The system of  claim 16 , wherein the impact tool actuates in response to a compressible fluid flowed through the coiled tubing to the impact tool. 
     
     
         22 . The system of  claim 16 , wherein the impact tool actuates in response to an incompressible fluid flowed through the coiled tubing to the impact tool. 
     
     
         23 . The system of  claim 16 , wherein the impact tool comprises a fluid hammer. 
     
     
         24 . The system of  claim 16 , wherein the impact tool comprises a pneumatic hammer. 
     
     
         25 . The system of  claim 16 , further comprising a shock absorber interconnected between the coiled tubing and the impact tool. 
     
     
         26 . The system of  claim 16 , wherein the impact tool actuates in response to a liquid flowed through the coiled tubing to the impact tool. 
     
     
         27 . The system of  claim 16 , wherein the impact tool actuates in response to a gas flowed through the coiled tubing to the impact tool. 
     
     
         28 . The system of  claim 27 , wherein the gas comprises nitrogen. 
     
     
         29 . The system of  claim 27 , wherein the gas is substantially free of oxygen. 
     
     
         30 . The system of  claim 27 , wherein the impact tool actuates in response to, along with the gas, additional one or more components selected from a lubricant, a friction reducer, a foam, oil, a mist, drilling mud, and water, flowed through the coiled tubing to the impact tool.