Apparatus and method for dewatering low pressure gradient gas wells

Abstract

Disclosed is an apparatus and method for removing extraneous water from a natural gas well using a miniaturized jet pump assembly and a concentric coiled tubing string. The miniaturized jet pump assembly is attached to a concentric coiled tubing string at the surface and then run into the well as a single unit. Alternatively, the concentric coiled tubing string may be assembled in the well. Once downhole, the jet pump assembly is activated to remove extraneous water from the well thereby facilitating the production of natural gas. Should the functional portion of the jet pump assembly corrode or wear out, that portion may be uninstalled and replaced without removing the jet pump assembly and concentric coiled tubing string from the well.

1 . A method for lowering a concentric coiled tubing string into a wellbore, the method comprising: 
 attaching a seating assembly to a lower end of an outer coiled tubing string;    lowering the seating assembly and the outer coiled tubing string into the wellbore through a production tubing string;    cutting an upper end of the outer coiled tubing string and suspending the outer coiled tubing string above the production tubing string;    attaching a jet pump assembly to a lower end of an inner coiled tubing string;    lowering the jet pump assembly and the inner coiled tubing string into the outer coiled tubing string until the jet pump assembly seats in the seating assembly; and    cutting an upper end of the inner coiled tubing string and suspending the the inner coiled tubing string above the production tubing string.    
   
   
       2 . The method of  claim 1 , wherein the step of attaching the seating assembly to the lower end of the outer coiled tubing string further includes attaching at least one flapper valve below the seating assembly.  
   
   
       3 . The method of  claim 2 , wherein the step of attaching a seating assembly to a lower end of the outer coiled tubing string further includes attaching a blow out plug below the seating assembly and the flapper valve(s).  
   
   
       4 . The method of  claim 1 , wherein the step of attaching the seating assembly to the lower end of the outer coiled tubing string further includes providing a sealing bore with the seating assembly.  
   
   
       5 . The method of  claim 1 , wherein the step of attaching the jet pump assembly to the lower end of the inner coiled tubing string further includes attaching a strainer to the inner coiled tubing string below the jet pump assembly.  
   
   
       6 . The method of  claim 5 , wherein the step of attaching the jet pump assembly to the lower end of the inner coiled tubing string further includes attaching a sealing assembly to the inner coiled tubing string below the jet pump assembly and above the strainer.  
   
   
       7 . The method of  claim 1 , wherein the jet pump assembly acts as a mechanical barrier to fluid flow through the inner coiled tubing string.  
   
   
       8 . The method of  claim 1 , wherein the step of lowering the outer coiled tubing string and the seating assembly into the wellbore further comprises lowering the outer coiled tubing string and the seating assembly through a Christmas tree.  
   
   
       9 . The method of  claim 1 , wherein the step of lowering the inner coiled tubing string and the jet pump assembly into the wellbore further comprises lowering the inner coiled tubing string and the jet pump assembly through a Christmas tree.  
   
   
       10 . The method of  claim 8 , wherein the step of lowering the outer coiled tubing string and the seating assembly through a Christmas tree further comprising attaching a slip bowl to the upper end of the outer coiled tubing string.  
   
   
       11 . The method of  claim 9 , wherein the step of lowering the inner coiled tubing string and the seating assembly through a Christmas tree further comprising attaching a slip bowl to the upper end of the inner coiled tubing string.  
   
   
       12 . The method of claims  10 , wherein the step of attaching a slip bowl to the upper end of the outer coiled tubing string further comprises suspending the slip bowl in a spool piece.  
   
   
       13 . The method of claims  11 , wherein the step of attaching a slip bowl to the upper end of the inner coiled tubing string further comprises suspending the slip bowl in a spool piece.  
   
   
       14 . The method of  claim 1 , further comprising constructing the outer coiled tubing string of corrosion resistant coiled tubing.  
   
   
       15 . The method of  claim 1 , further comprising constructing that portion of the outer coiled tubing string that extends across a perforation in the wellbore of corrosion resistant coiled tubing.  
   
   
       16 . A method for lowering a concentric coiled tubing string into a wellbore, the method comprising: 
 attaching a seating assembly to a lower end of an outer coiled tubing string;    lowering the seating assembly and the outer coiled tubing string into the wellbore through a production tubing string;    cutting an upper end of the outer coiled tubing string;    suspending the outer coiled tubing string above the production tubing string using suspending means;    attaching a jet pump assembly to a lower end of an inner coiled tubing string;    lowering the jet pump assembly and the inner coiled tubing string into the outer coiled tubing string until the jet pump assembly seats in the seating assembly; and    cutting an upper end of the inner coiled tubing string; and    suspending the inner coiled tubing string above the production tubing string using the suspending means.    
   
   
       17 . A method for removing a concentric coiled tubing string from a wellbore, wherein the concentric coiled tubing string comprises an outer coiled tubing string positioned within a production tubing string, and an inner coiled tubing string located within the outer coiled tubing string, the method comprising: 
 removing a portion of a jet pump assembly from the wellbore, wherein the jet pump assembly is attached to the lower end of the inner coiled tubing string;    lowering a portion of a dummy jet pump assembly into the natural gas wellbore through the inner coiled tubing string;    seating the dummy jet pump assembly in a seating assembly attached to the lower end of the outer coiled tubing string, wherein the jet pump dummy assembly prohibits fluid flow through the inner coiled tubing string;    removing the inner coiled tubing string and the jet pump dummy assembly from the wellbore;    lowering a wireline plug into the wellbore through the outer coiled tubing string;    seating the wireline plug in the seating assembly attached to the lower end of the outer coiled tubing string, wherein the wireline plug prohibits fluid flow through the outer coiled tubing string toward the surface position; and    removing the outer coiled tubing string and the wireline plug from the wellbore.