Pressure responsive centralizer

Abstract

A centralizer including hollow structural components. In at least one embodiment, the hollow structural component is sealed by at least one valve or rupture disk. When unacceptable overpressures occur, the valve or rupture disks break to allow influx into the hollow element, thereby relieving pressure and avoiding damage that might otherwise occur. In other embodiments, the hollow structural component collapses to expand available volume.

1 . A method of avoiding overpressure in a borehole, comprising opening a sealed hollow structural component within the borehole to thereby relieve overpressure by volumetric expansion into the hollow structural component.  
   
   
       2 . The method of  claim 1  wherein the hollow structural component is sealed by at least one relief valve.  
   
   
       3 . The method of  claim 1  wherein the hollow structural component is sealed by at least one rupture disk.  
   
   
       4 . The method of  claim 1  wherein the hollow structural component is attached to a centralizer providing axial support for downhole equipment.  
   
   
       5 . The method of  claim 1  wherein the hollow structural component is placed along a downhole string.  
   
   
       6 . The method of  claim 1  wherein the hollow structural component includes a first seal and a second seal.  
   
   
       7 . The method of  claim 6  wherein the first seal is a relief valve or rupture disk and the second seal is a relief valve or rupture disk.  
   
   
       8 . The method of  claim 7  wherein the first seal and second seal are calibrated to respond to the same level of overpressure.  
   
   
       9 . The method of  claim 7  wherein the first seal is calibrated to respond to a different level of overpressure than the second seal.  
   
   
       10 . A method of avoiding overpressure in a borehole, comprising relieving overpressure within the borehole by collapsing at least part of a hollow structural component.  
   
   
       11 . The method of  claim 10  wherein the hollow structural component is attached to a centralizer unit providing axial support for downhole equipment.  
   
   
       12 . The method of  claim 11  wherein the hollow structural component is placed along a downhole string.  
   
   
       13 . The method of  claim 12  further comprising a second hollow structural component that is sealed.  
   
   
       14 . The method of  claim 13  wherein the second hollow structural component is sealed by a relief valve or rupture disk.  
   
   
       15 . The method of  claim 14  wherein the first and second hollow structural components are calibrated to respond to the same overpressure.  
   
   
       16 . The method of  claim 14  wherein the first hollow structural component is calibrated to respond to a different level of overpressure than the second hollow structural component.  
   
   
       17 . A method of relieving overpressure in a borehole, comprising: 
 inserting a hollow structural component into the borehole;    increasing pressure within the borehole; and    relieving overpressure in the borehole by increasing the available volume in the borehole through a change in the hollow structural component.    
   
   
       18 . The method of  claim 17  wherein the available volume in the borehole is increased by opening the hollow structural component.  
   
   
       19 . The method of  claim 18  wherein the hollow structural component is sealed by a relief valve or rupture disk.  
   
   
       20 . The method of  claim 17  wherein volumetric expansion is created by collapsing of the hollow structural component.