Downhole packer

Abstract

A downhole packer is provided for sealing an annulus between first tubing located within larger diameter second tubing. The packer comprises a mandrel for coupling to the first tubing, the mandrel having a wall defining a main through bore and a plurality of smaller diameter through bores for receiving control lines. A seal arrangement is located on the mandrel and is configurable, in a set configuration, to form a seal with the surrounding larger diameter second tubing. A slip arrangement is located on the mandrel and is configurable, in a set configuration, to engage the surrounding larger diameter second tubing.

We claim:  
     
         1 . A resettable downhole packer for sealing an annulus between first tubing located within larger diameter second tubing, the packer comprising: 
 a mandrel for coupling to first tubing, the mandrel having a wall defining a main through bore and a plurality of smaller diameter through bores for receiving control lines;    a seal arrangement located on the mandrel and being configurable, in a set configuration, to form a seal with a surrounding larger diameter second tubing; and    a slip arrangement located on the mandrel and being configurable, in a set configuration, to engage the surrounding larger diameter second tubing,    the seal and slip arrangements being adapted to be reconfigured downhole from the set configuration to an unset configuration, and then further reconfigured downhole from the unset configuration to a reset configuration.    
     
     
         2 . The packer of  claim 1 , in combination with a plurality of control lines, each control line extending through a respective smaller diameter through bore.  
     
     
         3 . The packer of  claim 2 , in combination with control lines for communication with an electrically powered device, the control lines comprising power supply cables.  
     
     
         4 . The packer of  claim 3 , in combination with power supply cables for carrying a three phase electrical supply, wherein the individual phases are carried by respective individual cables located in respective smaller diameter through bores.  
     
     
         5 . The packer of  claim 1 , wherein at least the mandrel wall is formed from a single piece of material.  
     
     
         6 . The packer of  claim 5 , wherein the smaller diameter bores are gun drilled through the mandrel wall.  
     
     
         7 . The packer of  claim 1 , wherein the mandrel has an outside diameter and the main through bore has a inside diameter, said outside diameter and said inside diameter being offset to provide a relatively thick wall portion in which the smaller diameter through bores are formed.  
     
     
         8 . The packer of  claim 1 , wherein the smaller diameter through bores are circumferentially spaced about the main through bore.  
     
     
         9 . The packer of  claim 1 , wherein the packer is adapted to be hydraulically set.  
     
     
         10 . The packer of  claim 1 , wherein the packer is adapted to be hydraulically set by application of bore pressure.  
     
     
         11 . The packer of  claim 1 , further comprising a setting arrangement including a setting piston which is axially movable in response to elevated fluid pressure.  
     
     
         12 . The packer of  claim 11 , wherein the setting piston is an annular piston located substantially concentrically about the mandrel.  
     
     
         13 . The packer of  claim 11 , wherein the setting arrangement includes at least two operatively linked setting pistons.  
     
     
         14 . The packer of  claim 13 , wherein the at least two setting pistons are axially spaced.  
     
     
         15 . The packer of  claim 1 , wherein release of the seal arrangement and the slip arrangement from the set configuration results from release of a releasable coupling between a packer body mounted on the mandrel comprising elements of the seal arrangement and the slip arrangement, and the mandrel.  
     
     
         16 . The packer of  claim 1 , further comprising a spring mounted concentrically on the mandrel, the spring being adapted to facilitate resetting of the seal and slip arrangements.  
     
     
         17 . The packer of  claim 1 , further comprises a lost motion arrangement, including means for biassing a packer body, mounted on the mandrel and comprising elements of the seal arrangement and slip arrangement, towards a configuration ready for resetting the seal and slip arrangements, following release of the packer from the initial set position.  
     
     
         18 . The packer of  claim 17 , wherein the biassing means comprises a spring.  
     
     
         19 . The packer of  claim 18 , wherein the spring is mounted concentrically on the mandrel.  
     
     
         20 . The packer of  claim 19 , wherein the spring is initially restrained by a releasable coupling.  
     
     
         21 . The packer of  claim 20 , wherein the releasable coupling also serves to retain the seal and slip arrangements in the set configuration.  
     
     
         22 . The packer of  claim 1 , wherein the packer is adapted to be released from the reset configuration, to release the seal arrangement and the slip arrangement from the reset configuration, and allow retrieval of the packer.  
     
     
         23 . The packer of  claim 1 , wherein the packer is adapted to be released from the reset configuration, to release the seal arrangement and the slip arrangement from the reset configuration, and allow retrieval of the packer, release of the packer from the reset configuration resulting from the release of a releasable coupling between the packer body and the mandrel.  
     
     
         24 . A downhole packer for sealing an annulus between first tubing located within larger diameter second tubing, the packer comprising: 
 a mandrel for coupling to first tubing, the mandrel having a wall defining a main through bore and a plurality of smaller diameter through bores;    a seal arrangement located on the mandrel and being configurable, in a set configuration, to form a seal with a surrounding larger diameter second tubing;    a slip arrangement located on the mandrel and being configurable, in a set configuration, to engage the surrounding larger diameter second tubing; and    control lines for communication with an electrically powered downhole device below the packer, the control lines comprising power supply cables for carrying a three phase electrical supply, wherein the individual phases of the electrical supply are carried by three separate cables, each cable being located in a respective smaller diameter through bore in the mandrel wall.    
     
     
         25 . A downhole packer for sealing an annulus between first tubing located within larger diameter second tubing, the packer comprising: 
 a mandrel for coupling to first tubing, the mandrel having a wall defining a main through bore and a plurality of smaller diameter through bores;    a seal arrangement located on the mandrel and being configurable, in a set configuration, to form a seal with a surrounding larger diameter second tubing;    a slip arrangement located on the mandrel and being configurable, in a set configuration, to engage the surrounding larger diameter second tubing; and    a setting arrangement including at least two operatively associated setting pistons which are axially movable in response to elevated fluid pressure.    
     
     
         26 . The packer of  claim 25 , wherein the setting pistons are annular pistons located substantially concentrically about the mandrel.