Hydraulic Sleeve with Early Release Prevention

Abstract

A downhole window tool includes an internal sleeve slidably received within an outer housing. The sleeve and outer housing may have windows that selectively align or the sleeve may move out of alignment with the window to allow fluid passage through a window. Sleeve movement within the housing is controlled by inserting a dart or plug in the interior of the sleeve to allow pressure to act on the plug or dart to move the sleeve a set amount to open the lateral window. A shear pin or other device may be used to control the amount of force necessary to open the window and further ensure unintended opening of the lateral window. The use of the removable dart or plug both prevents unintentional forces from opening the window and increases the amount of throughput through the sleeve as compared to when valve structure is installed within the tool.

1 . A method of selectively uncovering a lateral opening in a downhole window tool comprising:
 providing an outer housing  12  having a generally tubular shape and a first lateral opening therethrough;   providing a tubular sleeve coaxial with and slidably received within said outer housing, said tubular sleeve having a second lateral opening therethrough;   installing said tubular sleeve in a first position within said outer housing such that said first lateral opening is out of alignment with said second lateral opening whereby there is no fluid communication through the first and second later openings between a first zone defined within said tubular sleeve and a second zone outside of said outer housing;   installing said outer housing on a drill string and lowering said drill string within a well bore;   lowering a bridge plug through said drill string to said first zone until said bridge plug abuts an abutment on an inner wall of said tubular sleeve;   pressurizing said first zone through said drill string, whereby pressure on said bridge plug acts on said abutment to move said inner sleeve relative to said outer housing from said first position to a second position wherein said first and second lateral openings are aligned to provide fluid communication between said first and second zones.   
     
     
         2 . The method of  claim 1 , wherein installation of the tubular sleeve in the first position includes affixing the tubular sleeve in place by shear pinning the tubular sleeve to the outer housing. 
     
     
         3 . The method of  claim 1 , wherein the outer housing is connected to said drill string by an upper sub. 
     
     
         4 . The method of  claim 1 , wherein said bridge plug completely blocks fluid flow through to a lower end of said tubular sleeve. 
     
     
         5 . A method of selectively uncovering a lateral opening in a downhole window tool comprising:
 providing an outer housing having a generally tubular shape and a first lateral opening therethrough;   providing a tubular sleeve coaxial with and slidably received within said outer housing, said tubular sleeve having a second lateral opening therethrough;   installing said tubular sleeve in a first position within said outer housing such that said first lateral opening is out of alignment with said second lateral opening whereby there is no fluid communication through the first and second later openings between a first zone defined within said tubular sleeve and a second zone outside of said outer housing;   installing said outer housing on a drill string and lowering said drill string within a well bore;   lowering a dart through said drill string to said first zone until said dart bridge plug abuts an abutment on an inner wall of said tubular sleeve;   pressurizing said first zone through said drill string, whereby pressure on said dart bridge plug acts on said abutment to move said inner sleeve relative to said outer housing from said first position to a second position wherein said first and second lateral openings are aligned to provide fluid communication between said first and second zones.   
     
     
         6 . The method of  claim 1 , wherein installation of the tubular sleeve in the first position includes affixing the tubular sleeve in place by shear pinning the tubular sleeve to the outer housing. 
     
     
         7 . The method of  claim 1 , wherein the outer housing is connected to said drill string by an upper sub. 
     
     
         8 . The method of  claim 1 , wherein said dart bridge plug completely blocks fluid flow through to a lower end of said tubular sleeve. 
     
     
         9 . A method of selectively uncovering a lateral opening in a downhole window tool comprising:
 providing an outer housing on said downhole window tool having a generally tubular shape and a first lateral opening therethrough;   providing a tubular sleeve coaxial with and slidably received within said outer housing, said tubular sleeve having a second lateral opening therethrough;   pinning said tubular sleeve in a first position within said outer housing such that said first lateral opening is out of alignment with said second lateral opening whereby there is no fluid communication through the first and second later openings between a first zone defined within said tubular sleeve and a second zone outside of said outer housing;   lowering said downhole window tool on a drill string drill string within a well bore;   pressurizing said first zone to cause flow from above said first zone through said tubular sleeve to an area below said first zone;   lowering a bridge plug through said drill string to said first zone until said bridge plug abuts an abutment on an inner wall of said tubular sleeve;   pressurizing said first zone through said drill string, whereby pressure on said bridge plug acts on said abutment to move said inner sleeve relative to said outer housing from said first position to a second position wherein said first and second lateral openings are aligned to provide fluid communication between said first and second zones;   whereby further pressurization of said first zone causes flow to flow from above first zone through said first and second lateral opening to said second zone.   
     
     
         10 . The method of  claim 1 , wherein pinning the tubular sleeve in the first position includes affixing the tubular sleeve in place by shear pinning the tubular sleeve to the outer housing. 
     
     
         11 . The method of  claim 1 , wherein the outer housing is connected to said drill string by an upper sub. 
     
     
         12 . The method of  claim 1 , wherein said dart bridge plug completely blocks fluid flow through to a lower end of said tubular sleeve.