Downhole apparatus

Abstract

A method of setting a packer in a bore comprises the steps: mounting a packer on an elongate support member; mounting a casing scraper ( 10 ) on the elongate member; running the packer and the casing scraper ( 10 ) into a bore on the elongate member to a section of the bore where the packer is to be set; cleaning the section of bore with the scraper ( 10 ); and setting the packer in the cleaned section of bore. The scraper ( 10 ) comprises: a mandrel ( 22 ) adapted for coupling to the elongate member; a sleeve ( 14 ) mounted on the mandrel ( 22 ); and a plurality of scraper members ( 16 ) on the sleeve ( 14 ), the members ( 16 ) being radially movable relative to the mandrel ( 22 ).

We claim:  
     
         1 . A method of setting a packer in a drilled bore, the method comprising: 
 mounting a packer on an elongate member;    mounting a casing scraper on the elongate member;    running the packer and the casing scraper into a bore on the elongate member to a section of the bore where the packer is to be set;    cleaning said section of bore with the scraper; and    setting the packer in the cleaned section of bore.    
     
     
         2 . The method of    claim 1   , wherein the packer and casing scraper are released from the elongate member once the packer has been set, such that the elongate member may then withdrawn from the bore while the packer and scraper remain in the bore.  
     
     
         3 . A casing scraper comprising a body and means for mounting the body to a packer so that the scraper may be run into a drilled bore on an elongate member together with the packer.  
     
     
         4 . The casing scraper of    claim 3   , wherein the mounting means is operative to mount the scraper below the packer.  
     
     
         5 . The casing scraper of    claim 4   , wherein the mounting means is operative to mount the scraper directly to the packer.  
     
     
         6 . The casing scraper of    claim 3   , wherein the scraper comprises cleaning members having a radial extent selected to be similar to or greater than the diameter of the bore section to be cleaned.  
     
     
         7 . The casing scraper of    claim 6   , wherein the cleaning members are in the form of blades.  
     
     
         8 . The casing scraper of    claim 6   , wherein the cleaning members are resiliently mounted on the body.  
     
     
         9 . The casing scraper of    claim 8   , wherein the cleaning members are mounted on a sleeve.  
     
     
         10 . The casing scraper of    claim 9   , wherein the sleeve is of resilient material.  
     
     
         11 . The casing scraper of    claim 9   , wherein the sleeve is formed of a plurality of rigid sections which are radially movable relative to the body.  
     
     
         12 . The casing scraper of    claim 8   , wherein springs are provided for biassing the cleaning members outwardly.  
     
     
         13 . The casing scraper of    claim 12   , further comprising a cleaning member mounting sleeve and wherein the springs are located internally of the sleeve.  
     
     
         14 . The casing scraper of    claim 6   , wherein the members extend helically.  
     
     
         15 . The casing scraper of    claim 14   , further comprising junk slots extending longitudinally through the members, to allow debris to flow past the members.  
     
     
         16 . The casing scraper of    claim 15   , wherein the slots extend obliquely, such that the cleaning members provide 360° coverage.  
     
     
         17 . The casing scraper of    claim 6   , further comprising a sleeve and a mandrel and wherein the cleaning members are mounted on the sleeve which is itself supported on the mandrel.  
     
     
         18 . The casing scraper of    claim 17   , wherein the sleeve is removably mounted on the mandrel.  
     
     
         19 . The casing scraper of    claim 18   , further comprising end stops and wherein the sleeve is mounted between the end stops.  
     
     
         20 . The casing scraper of    claim 19   , wherein at least one of the stops is removable to facilitate removal and replacement of the sleeve.  
     
     
         21 . The casing scraper of    claim 19   , wherein the stops cooperate with the sleeve to limit radial movement of the sleeve.  
     
     
         22 . The casing scraper of    claim 3   , in combination with a bull-nosed centraliser.  
     
     
         23 . A downhole casing scraper for mounting on an elongate member for running the scraper into a drilled bore, the scraper comprising: 
 a mandrel; a sleeve mounted on the mandrel; and a plurality of scraper members on the sleeve, the members being radially movable relative to the mandrel.