Method and system for installing a tubular element in a borehole

Abstract

A radially expandable tubular element ( 1 ) is installed in an underground borehole by:—lowering the tubular element ( 1 ) into the borehole a work string ( 2 ) and an anchor tool ( 16 ) to which the tubular element ( 1 ) is connected via a dimple connection ( 32 ) to increase the weight carrying capacity of the anchor tool ( 16 );—connecting an expander ( 14 ) to the work string ( 2 ) at a position below the anchor tool ( 16 ); and—radially expanding the tubular element ( 1 ) by pulling the expander ( 14 ) on the work string ( 2 ) through the tubular element ( 1 ).

1 . A method of installing a radially expandable tubular element in an underground borehole comprises the steps of:
 (a) positioning in the tubular element an anchor tool having a cylindrical outer surface provided with at least one dimple;   (b) operating a pressing device to press a respective wall portion of the tubular element into the at least one dimple to create a dimple connection between the tubular element and the anchor tool;   (c) providing a work string connected to the anchor tool;   (d) operating a drive device to lower the tubular element into the borehole on the work string when the tubular element is connected to the anchor tool via the dimple connection;   (e) connecting an expander to the work string at a position below the anchor tool; and   (f) radially expanding the tubular element by pulling the expander on the work string through the tubular element.   
     
     
         2 . The method of  claim 1 , wherein the step of operating the pressing device comprises pressing a die member against said wall portion of the tubular element, the die member having an end portion with a shape similar to the shape of the dimple. 
     
     
         3 . The method of  claim 1 , further comprising releasing the anchor tool from the tubular element by inducing the drive device to move the work string in at least one of axial and rotational direction relative to the tubular element to deform each said wall portion to a shape substantially similar to the shape of the wall portion prior to the step of operating the pressing device. 
     
     
         4 . A system for installing a radially expandable tubular element in an underground borehole, the system comprising:
 (a) an anchor tool adapted to be positioned in the tubular element and having a cylindrical outer surface provided with at least one dimple;   (b) a pressing device for pressing a respective wall portion of the tubular element opposite the at least one dimple into the dimple, to create a dimple connection between the tubular element and the anchor tool;   (c) a work string connected to the anchor tool;   (d) a drive device for lowering the tubular element into the borehole on the work string when the tubular element is connected to the anchor tool via the dimple connection;   (e) means for connecting an expander to the work string at a position below the anchor tool; and   (f) means for radially expanding the tubular element by pulling the expander on the work string through the tubular element.   
     
     
         5 . The system of  claim 4 , wherein the at least one dimple has a first surface and a second surface arranged opposite each other and extending in circumferential direction of the anchor tool, said first and second surfaces having mutually different inclination angles relative to the cylindrical outer surface. 
     
     
         6 . The system of  claim 5 , wherein the first surface extends at an inclination angle α1 and the second surface at an inclination angle α2 relative to the cylindrical outer surface, the first surface facing upwardly in the borehole. 
     
     
         7 . The system of  claim 6 , wherein α1>α2. 
     
     
         8 . The system of  claim 6 , wherein a rounded transition surface extends between the second surface and the cylindrical outer surface. 
     
     
         9 . The system of  claim 5 , wherein the dimple has a bottom surface located between the first surface and the second surface, the bottom surface extending substantially parallel to a longitudinal axis of the anchor tool. 
     
     
         10 . The system of  claim 9 , wherein the bottom surface has a truncated V-shape. 
     
     
         11 . The system of  claim 4 , wherein the cylindrical outer surface of the anchor tool is provided with a plurality of said dimples spaced in circumferential direction of the anchor tool. 
     
     
         12 . The system of  claim 4 , wherein the pressing device includes a die member having an end portion with a shape similar to the shape of the dimple. 
     
     
         13 . The system of  claim 12 , wherein the pressing device comprises positioning means connectable to the anchor tool and adapted to move the anchor tool relative to the die member so that the dimple is located opposite the die member. 
     
     
         14 . The system of  claim 4 , wherein the tubular element is a radially expandable tubular element, and wherein the system further comprises an expander for radially expanding the tubular element by axially moving the expander through the tubular element, the expander being connected to the work string at a position below the anchor tool.