Debris Interface Control Device for Wellbore Cleaning Tools

Abstract

A spacing device is located on a lower end of a debris removal tool. Circulation through the tool extends telescoping members to the top of the debris zone against a bias that retracts the members when there is no flow through the tool. The lowest telescoping member has peripheral slots through which the circulation for the tool takes place. The landing of the tool on top of the debris can be detected by the weight indicator at the surface. The device prevents embedding the lower end of the tool into the debris. Instruments can also determine the scope of the telescoping extension and transmit that value to the surface so that the cleanup tool can be continuously spaced from the moving top of the debris pile by maintaining a target distance for extension of the telescoping assembly.

We claim: 
     
         1 . A spacer for a lower end of a subterranean removal tool for debris, comprising:
 a tubular housing defined by a wall having an open upper and lower end, the upper end supported by the tool and further comprising at least one opening in said wall so that when said lower end is in contact with the debris to be removed, fluid flow with respect to the tool with entrained debris can occur through said opening while spacing the tool from the debris.   
     
     
         2 . The spacer of  claim 1 , wherein:
 said housing has multiple components.   
     
     
         3 . The spacer of  claim 2 , wherein:
 said components coaxially or eccentrically telescope.   
     
     
         4 . The spacer of  claim 3 , wherein:
 said components move responsive to pressure that creates fluid flow.   
     
     
         5 . The spacer of  claim 4 , wherein:
 said components extend with respect to each other responsive to pressure that creates fluid flow.   
     
     
         6 . The spacer of  claim 5 , wherein:
 said components are biased toward a collapsed position.   
     
     
         7 . The spacer of  claim 3 , wherein:
 said opening remains open when said components fully collapse.   
     
     
         8 . The spacer of  claim 7 , wherein:
 said opening remains fully open when said components are fully extended or fully collapsed.   
     
     
         9 . The spacer of  claim 8 , wherein:
 said opening comprises at least one slot located on a lowermost component of said components.   
     
     
         10 . The spacer of  claim 9 , wherein:
 said at least one slot comprises a plurality of slots extending up from at or near lower end of said lowermost component.   
     
     
         11 . The spacer of  claim 3 , further comprising:
 a sensor to detect the amount of telescoping of said components;   a transmitter to a surface location of the reading of said sensor of the degree of telescoping extension.   
     
     
         12 . The spacer of  claim 11 , wherein:
 said sensor allows a lowermost component of said housing to stay in contact with a top surface of the debris as debris is removed into the tool.   
     
     
         13 . A method of operating a debris removal tool at a subterranean location comprising:
 connecting a spacer near a lower end of the debris removal tool;   configuring the spacer to have at least one wall opening;   running in the tool to a location where the spacer engages a top surface of debris at the subterranean location;   using said spacer to hold a lower end of the debris removal tool from the debris top surface while flow goes through said opening for retaining the debris in the tool.   
     
     
         14 . The method of  claim 13 , comprising:
 using multiple coaxially or eccentrically telescoping components for said spacer.   
     
     
         15 . The method of  claim 14 , comprising:
 placing said wall opening in a lowermost component of said components.   
     
     
         16 . The method of  claim 14 , comprising:
 using pressure from said flow to extend said telescoping components.   
     
     
         17 . The method of  claim 14 , comprising:
 keeping said opening at least part way open when said components telescope to their shortest dimension.   
     
     
         18 . The method of  claim 14 , comprising:
 positioning a lower end of a lowermost component on a debris top surface with said components telescoped in;   allowing said components to telescope out to maintain contact of said lowermost component with the moving top of the debris as debris is collected in the tool while the tool is held stationary;   lowering the tool after said components telescopingly extend to allow said lowermost component to remain in contact with the moving top of the debris.   
     
     
         19 . The method of  claim 14 , comprising:
 sensing the amount of extension of said telescoping components;   transmitting to a surface location the sensed amount of extension of said telescoping components;   using the transmitted information to maintain a lowermost component in contact with a moving top surface of the debris as debris is removed and the tool is moved.   
     
     
         20 . The method of  claim 18 , comprising:
 sensing the amount of extension of said telescoping components;   transmitting to a surface location the sensed amount of extension of said telescoping components;   using the transmitted information to maintain a lowermost component in contact with a moving top surface of the debris as debris is removed and the tool is moved.