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 . An assembly for removing produced water from a wellbore, the assembly comprising: 
 an outer coiled tubing string capable of being inserted into a production tubing string;    an inner coiled tubing string contained within the outer coiled tubing string;    an annular channel formed between the inner coiled tubing string and the outer coiled tubing string;    an outer tubular member attached to a lower end of the outer coiled tubing string;    a pump housing contained within the outer tubular member and attached to a lower end of the inner coiled tubing string; and    a jet pump contained within the pump housing.    
   
   
       2 . The assembly of  claim 1 , further comprising a one-way valve attached to a lower end of the pump housing, the one-way valve located below the jet pump.  
   
   
       3 . The assembly of  claim 1 , wherein the jet pump comprises a jet nozzle, a throat, an upper diffuser, and a lower diffuser.  
   
   
       4 . The assembly of  claim 1 , further comprising a first sealing assembly located between an outer surface of the jet pump and an inner surface of the pump housing.  
   
   
       5 . The assembly of  claim 3 , further comprising a second sealing assembly located between an outer surface of the upper diffuser and an inner surface of the lower diffuser.  
   
   
       6 . The assembly of  claim 1 , further comprising a third sealing assembly located between an outer surface of the pump housing and an inner surface of the outer tubular member.  
   
   
       7 . The assembly of  claim 1 , wherein the jet pump further comprises a fishing neck.  
   
   
       8 . The assembly of  claim 1 , further comprising a second annular channel formed between the jet pump and the pump housing.  
   
   
       9 . The assembly of  claim 8 , further comprising a port that is in fluid communication with the jet pump and the second annular fluid channel.  
   
   
       10 . The assembly of  claim 1 , further comprising a boot sub attached to a lower end of the outer tubular member and a lower end of the pump housing.  
   
   
       11 . The assembly of  claim 10 , wherein the boot sub comprises an open lower end in fluid communication with the natural gas wellbore.  
   
   
       12 . The assembly of  claim 4 , wherein at least a portion of the jet pump can be removed from the pump housing using hydraulic pressure while the jet pump is located in the wellbore.  
   
   
       13 . The assembly of  claim 7 , wherein at least a portion of the jet pump can be removed from the pump housing using a wire-line fishing tool while the jet pump is located in the wellbore.  
   
   
       14 . The assembly of  claim 1 , wherein the production tubing string has an outer diameter less than or equal to 2-⅞ inches.  
   
   
       15 . The assembly of  claim 1 , wherein the outer coiled tubing string has an outer diameter less than or equal to 2 inches.  
   
   
       16 . The assembly of  claim 1 , wherein the inner coiled tubing string has an outer diameter less than or equal to 1 inch.  
   
   
       17 . The assembly of  claim 1 , wherein the jet pump has an outer diameter of less than 1 inch.  
   
   
       18 . The assembly of  claim 1 , wherein the outer coiled tubing string is composed of corrosion resistant coiled tubing.  
   
   
       19 . The assembly of  claim 1 , wherein that portion of the outer coiled tubing string that extends across a perforation in the wellbore is comprised of corrosion resistant coiled tubing.  
   
   
       20 . An assembly for removing produced water from a wellbore, the assembly comprising: 
 an outer jointed tubing string capable of being inserted into a production tubing string, wherein at least a portion of the outer jointed tubing string is made of a corrosion resistant material;    an inner coiled tubing string contained within the outer jointed tubing string;    an annular channel formed between the inner coiled tubing string and the outer jointed tubing string;    an outer tubular member attached to a lower end of the outer jointed tubing string;    a pump housing contained within the outer tubular member and attached to a lower end of the inner coiled tubing string; and    a jet pump contained within the pump housing.    
   
   
       21 . The assembly of  claim 20 , wherein the portion of the outer jointed tubing string that extends across perforations in the wellbore is made of corrosion resistant material.  
   
   
       22 . A method for removing produced water from a wellbore, the method comprising: 
 attaching a jet pump assembly to a lower end of a concentric coiled tubing string, the concentric coiled tubing string comprising an outer coiled tubing string, an inner coiled tubing string contained within the outer coiled tubing string, and an annular fluid channel formed there between;    lowering the jet pump assembly and concentric coiled tubing string through a production tubing string;    pumping a power fluid to the jet pump assembly through the inner coiled tubing string;    jetting the power fluid through the jet pump assembly to create an area of low pressure therein;    drawing the water from the wellbore into the jet pump assembly; and    pumping the water from the wellbore to the surface.    
   
   
       23 . The method of  claim 22 , wherein the step of returning the water from the wellbore to the surface further comprises returning the water from the wellbore to the surface through the annular fluid channel.  
   
   
       24 . The method of  claim 22 , further comprising providing the jet pump assembly with a one-way valve.  
   
   
       25 . The method of  claim 22 , further comprising constructing the outer coiled tubing with corrosion resistant coiled tubing.  
   
   
       26 . The method of  claim 22 , further comprising constructing that portion of the outer coiled tubing that extends across a perforation in the wellbore of corrosion resistant coiled tubing.  
   
   
       27 . The method of  claim 22 , further comprising providing the production tubing string with an outer diameter less than or equal to 2-⅞ inches.  
   
   
       28 . The method of  claim 22 , providing the outer coiled tubing string with an outer diameter less than or equal to 2 inches.  
   
   
       29 . The method of  claim 22 , providing the inner coiled tubing string with an outer diameter less than or equal to 1 inch.  
   
   
       30 . The method of  claim 22 , providing the jet pump assembly with an outer diameter less than or equal to 1 inch.  
   
   
       31 . The method of  claim 22 , further comprising removing at least a portion of the jet pump assembly from the wellbore without removing the concentric coiled tubing string from the wellbore.  
   
   
       32 . A method for removing produced water from a wellbore, the method comprising: 
 lowering an outer jointed tubing string into the wellbore, wherein the outer jointed tubing string is made of corrosion resistant material;    attaching a jet pump assembly to a lower end of an inner coiled tubing string;    lowering the jet pump assembly and inner coiled tubing string into the outer jointed tubing string;    providing an annular channel between the outer jointed tubing string and the inner coiled tubing string    pumping a power fluid to the jet pump assembly through the inner coiled tubing string;    jetting the power fluid through the jet pump assembly to create an area of low pressure therein;    drawing the water from the wellbore into the jet pump assembly; and    pumping the water from the wellbore to the surface.    
   
   
       33 . The method of  claim 32 , further comprising lowering the jet pump assembly past perforations in the wellbore, wherein the portion of the outer jointed tubing string that extends across the perforations is made of corrosion resistant material.  
   
   
       34 . A method for removing produced water from a wellbore, the method comprising: 
 attaching a jetting means to a lower end of a concentric coiled tubing string, the concentric coiled tubing string comprising an outer coiled tubing string, an inner coiled tubing string contained within the outer coiled tubing string, and an annular channel there between;    lowering the jetting means and concentric coiled tubing string through a production tubing string;    pumping a power fluid to the jetting means through the inner coiled tubing string;    jetting the power fluid through the jetting means to create an area of low pressure thererin;    drawing the water from the wellbore into the jetting means; and    pumping the water from the wellbore to the surface.    
   
   
       35 . The method of  claim 34 , wherein the step of returning the water from the wellbore to the surface further comprises returning the water from the wellbore to the surface through the annular fluid channel.  
   
   
       36 . The method of  claim 34 , further comprising removing at least a portion of the jetting means from the wellbore without removing the concentric coiled tubing from the wellbore.  
   
   
       37 . 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.    
   
   
       38 . The method of  claim 37 , 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.  
   
   
       39 . The method of  claim 38 , 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).  
   
   
       40 . The method of  claim 37 , 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.  
   
   
       41 . The method of  claim 37 , 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.  
   
   
       42 . The method of  claim 41 , 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.  
   
   
       43 . The method of  claim 37 , wherein the jet pump assembly acts as a mechanical barrier to fluid flow through the inner coiled tubing string.  
   
   
       44 . The method of  claim 37 , 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.  
   
   
       45 . The method of  claim 37 , 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.  
   
   
       46 . The method of  claim 44 , 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.  
   
   
       47 . The method of  claim 45 , 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.  
   
   
       48 . The method of claims  46 , 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.  
   
   
       49 . The method of claims  47 , 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.  
   
   
       50 . The method of  claim 37 , further comprising constructing the outer coiled tubing string of corrosion resistant coiled tubing.  
   
   
       51 . The method of  claim 37 , further comprising constructing that portion of the outer coiled tubing string that extends across a perforation in the wellbore of corrosion resistant coiled tubing.  
   
   
       52 . 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.    
   
   
       53 . 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.    
   
   
       54 . An assembly for removing produced water from a wellbore, the assembly comprising: 
 an outer coiled tubing string;    an inner coiled tubing string contained within the outer coiled tubing string;    an annular channel formed between the inner coiled tubing string and the outer coiled tubing string;    an outer tubular member attached to a lower end of the outer coiled tubing string;    a pump housing contained within the outer tubular member and attached to a lower end of the inner coiled tubing string; and    a jet pump contained within the pump housing, wherein at least a portion of the jet pump can be removed from the wellbore without removing either the outer coiled tubing string or the inner coiled tubing string.    
   
   
       55 . A method for removing produced water from a wellbore, the method comprising: 
 attaching a jet pump assembly to a lower end of a concentric coiled tubing string, the concentric coiled tubing string comprising an outer coiled tubing string, an inner coiled tubing string contained within the outer coiled tubing string, and an annular fluid channel formed there between;    lowering the jet pump assembly and concentric coiled tubing string into the wellbore;    pumping a power fluid to the jet pump assembly through the inner coiled tubing string;    jetting the power fluid through the jet pump assembly to create an area of low pressure therein;    drawing the water from the wellbore into the jet pump assembly;    pumping the water from the wellbore to the surface; and    removing at least a portion of the jet pump assembly from the wellbore without removing the concentric coiled tubing string.