Sealing Between Alignable Windows for Lateral Wellbore Drilling

Abstract

Sealing may be provided between alignable windows for lateral wellbore drilling. A method for use with a lateral wellbore includes the steps of: positioning a swellable seal material between a closure device and a housing of a window assembly; swelling the seal material to thereby prevent fluid transfer through a window formed in a sidewall of the housing; and then installing the window assembly in a parent wellbore. A lateral wellbore system includes a window assembly with a window formed through a sidewall of a generally tubular housing, and a swollen seal material preventing fluid transfer through the window. A window assembly includes a generally tubular housing having a window formed through a sidewall of the housing, a closure device having another window formed through a wall of the closure device; and a swellable seal material which prevents fluid transfer between the windows.

1 . A lateral wellbore system, comprising:
 a window assembly including a first window formed through a sidewall of a generally tubular housing, and a swollen seal material preventing fluid transfer through the first window.   
     
     
         2 . The system of  claim 1 , wherein the seal material is swollen prior to installation of the window assembly in a wellbore. 
     
     
         3 . The system of  claim 1 , wherein the window assembly further includes a second window formed through a wall of a closure device, and wherein the seal material prevents fluid transfer between the first and second windows. 
     
     
         4 . The system of  claim 3 , wherein the second window is displaceable into alignment with the first window, thereby permitting drilling of a lateral wellbore through the aligned first and second windows. 
     
     
         5 . The system of  claim 3 , wherein the closure device is rotatable to align the first and second windows. 
     
     
         6 . The system of  claim 3 , wherein the closure device is displaceable axially relative to the housing to align the first and second windows. 
     
     
         7 . The system of  claim 1 , wherein the window assembly further includes a closure device displaceable to open the first window, and wherein the seal material seals between the closure device and the housing. 
     
     
         8 . The system of  claim 1 , wherein the closure device is generally tubular in shape and is received within an interior of the housing. 
     
     
         9 . A method for use with a lateral wellbore, the method comprising the steps of:
 positioning a swellable seal material between a closure device and a housing of a window assembly;   swelling the seal material to thereby prevent fluid transfer through a first window formed in a sidewall of the housing; and   then installing the window assembly in a parent wellbore.   
     
     
         10 . The method of  claim 9 , further comprising the step of displacing the closure device relative to the housing, thereby permitting fluid transfer through the window. 
     
     
         11 . The method of  claim 10 , wherein the displacing step further comprises rotating the closure device relative to the housing. 
     
     
         12 . The method of  claim 10 , wherein the displacing step further comprises axially displacing the closure device relative to the housing. 
     
     
         13 . The method of  claim 10 , wherein the displacing step further comprises aligning the first window with a second window formed through the closure device. 
     
     
         14 . The method of  claim 13 , further comprising the step of drilling the lateral wellbore through the aligned first and second windows. 
     
     
         15 . The method of  claim 13 , wherein the swelling step further comprises preventing fluid transfer between the first and second windows. 
     
     
         16 . The method of  claim 9 , wherein the swelling step is performed only prior to the installing step. 
     
     
         17 . A window assembly for use in a subterranean well, the window assembly comprising:
 a generally tubular housing having a first window formed through a sidewall of the housing;   a closure device having a second window formed through a wall of the closure device; and   a swellable seal material which prevents fluid transfer between the first and second windows.   
     
     
         18 . The window assembly of  claim 17 , wherein the closure device is generally tubular in shape and is received within an interior of the housing. 
     
     
         19 . The window assembly of  claim 17 , wherein the seal material is swollen prior to installation of the window assembly in a wellbore. 
     
     
         20 . The window assembly of  claim 17 , wherein the second window is displaceable into alignment with the first window, thereby permitting drilling of a lateral wellbore through the aligned first and second windows.