Circulating coil cleanout tool and method

Abstract

The invention relates to a tool and method for cleaning a wellbore. The tool includes a tubing string comprising an upper end and a lower end, and defining a first bore for allowing passage of fluid from the wellbore to surface; a guide string disposed inside the tubing string and defining an internal bore to run coiled tubing therethrough, the coiled tubing carrying at least one jet nozzle; at least one seal disposed around the tubing string for sealing against a well casing; at least one port defined by the tubing string and positioned above the seal for allowing fluid to pass therethrough; and at least one valve positioned below the seal to allow fluid to pass upward through the valve but not downward.

What is claimed is: 
     
         1 . A downhole tool for cleaning a wellbore comprising:
 a) a tubing string comprising an upper end and a lower end, and defining a first bore for allowing passage of fluid from the wellbore to surface;   b) a guide string disposed inside the tubing string and defining an internal bore to run coiled tubing therethrough, the coiled tubing carrying at least one jet nozzle;   c) at least one seal disposed around the tubing string for sealing against a well casing;   d) at least one port defined by the tubing string and positioned above the seal for allowing fluid to pass therethrough; and   e) at least one valve positioned below the seal to allow fluid to pass upward through the valve but not downward.   
     
     
         2 . The tool of  claim 1 , wherein the seal comprises at least one ring-shaped V cup having an interior diameter substantially equal to the outside diameter of the tubing string. 
     
     
         3 . The tool of  claim 2 , wherein the seal comprises a pair of stacked V cups, an upper V cup being oriented upwardly and a lower V cup being oriented downwardly. 
     
     
         4 . The tool of  claim 1 , wherein the tubing string defines a pair of aligned, parallel spaced ports. 
     
     
         5 . The tool of  claim 1 , wherein the valve comprises a ball valve. 
     
     
         6 . The tool of  claim 1 , wherein the tubing string and guide string are threadless. 
     
     
         7 . The tool of  claim 1 , Wherein the guide string is sealed at its lower end. 
     
     
         8 . The tool of  claim 1 , comprising a drain or a sliding sleeve positioned between the seal and the valve. 
     
     
         9 . The tool of  claim 1 , wherein the guide string and valve are optional components. 
     
     
         10 . A method of cleaning a wellbore using the tool of  claim 1  comprising the steps of:
 a) running the tool into the wellbore in proximity to perforations; 
 b) pumping circulation fluid into an annulus defined between the tool and well casing under sufficient pressure to force the circulation medium upwardly through the port into the tubing string to surface, wherein formation fluid and debris are suctioned upwardly into the tubing string; 
 c) running coiled tubing into the guide string to position the jet nozzle in proximity to the perforations; 
 d) pumping cleaning fluid into the coiled tubing to create a jet stream of fluid; and 
 e) continuously pumping the circulation medium and cleaning fluid for conveying formation fluid and debris upwardly from the wellbore to surface. 
 
     
     
         11 . The method of  claim 10 , wherein the guide string and valve are omitted from the tool. 
     
     
         12 . The method of  claim 10 , further comprising running a profile nipple into the wellbore to land a blanking plug. 
     
     
         13 . The method of  claim 10 , further comprising killing the wellbore and removing the tool from the killed wellbore. 
     
     
         14 . The method of  claim 13 , wherein kill fluid is pumped into the tubing string to blow a drain. 
     
     
         15 . The method of  claim 13 , wherein a sliding sleeve is actuated to allow fluid drainage.