Modular weight bar

Abstract

A modular weight bar usable in conjunction with downhole tools disposed within a pressurized wellbore. The modular weight bar adds mass to the downhole tool so it can be suspended and lowered within the pressurized wellbore on wireline. The modular weight bar is separatable from the downhole tool at a selected depth within the wellbore thereby allowing the downhole tool to be further lowered within the wellbore without being accompanied by the weight bar.

1 . A modular weight bar for use with a downhole tool comprising: 
 a body formed for insertion within a wellbore;    an engagement system formed to selectively engage the modular weight bar with the wellbore; and    a deployment system formed to releasably secure said modular weight bar to the downhole tool,    wherein included with the wellbore is at least one protrusion formed on the inner circumference of the wellbore.    
   
   
       2 . The modular weight bar of  claim 1 , wherein said body is configured to house and protect the downhole tool.  
   
   
       3 . The modular weight bar of  claim 1 , wherein said body encompasses the downhole tool and contains within said body hazardous material associated with the downhole tool.  
   
   
       4 . The modular weight bar of  claim 1 , wherein the weight of said modular weight bar is substantially equal to the weight of a length of wireline that suspends the modular weight bar and down hole tool at a selected depth within the wellbore.  
   
   
       5 . The modular weight bar of  claim 1 , where said deployment system comprises a rod disposed on the downhole tool having ridges formed on the outer surface of said rod, and corresponding ridges formed within an aperture formed on said body, where said aperture is situated substantially coaxial on said body.  
   
   
       6 . The modular weight bar of  claim 1 , wherein said engagement system comprises at least one latch tab formed on the outer surface of said body formed to contact said at least one protrusion formed on the inner circumference of the wellbore.  
   
   
       7 . The modular weight bar of  claim 1 , wherein said deployment system separates the wireline tool from said modular weight bar at a selected depth within the wellbore, thereby enabling the wireline tool to be deployed to a depth greater than the selected depth within the wellbore.  
   
   
       8 . The modular weight bar of  claim 1  further comprising at least one slip disposed on said body; and 
 a sliding sleeve moveable along said body to deploy said at least one slip into a securing position.    
   
   
       9 . The sliding sleeve of  claim 8  further comprising at least one latch tab secured to said sliding sleeve, said latch tab being formed to matingly contact said at least one protrusion formed on the inner circumference of the wellbore such that the sliding sleeve is moved along said body upon contact of said latch tab.  
   
   
       10 . The modular weight bar of  claim 8  wherein said slips are remotely activatable.  
   
   
       11 . The modular weight bar of  claim 10  wherein said slips are remotely activatable from a signal transmitted via a wireline connected to the wireline tool.  
   
   
       12 . The modular weight bar of  claim 8  wherein said slips are activated by hydraulic pressure.  
   
   
       13 . The modular weight bar of  claim 12  further comprising at least one rupture disk formed to rupture at a hydraulic pressure corresponding to a selected depth within the wellbore thereby securing and suspending said modular weight bar to the wellbore at the selected depth.  
   
   
       14 . The modular weight bar of  claim 12  further comprising a pressure chamber proximate to said sliding sleeve, whereby when the modular weight bar is disposed at the selected depth the hydrostatic pressure within the wellbore is sufficiently greater than the pressure within the pressure chamber to move the sliding sleeve into the pressure chamber thereby securing and suspending said modular weight bar to the wellbore at the selected depth.  
   
   
       15 . The modular weight bar of  claim 8  further comprising a tapered edge provided on said sliding sleeve, said tapered edge formed for insertion between said at least one slip and said body as said sliding sleeve is upwardly urged, thereby outwardly extending said at least one slip into engaging contact with the wellbore.  
   
   
       16 . The modular weight bar of  claim 1 , wherein said engagement system engages said modular weight bar within the wellbore and suspends said modular weight bar within the wellbore, thereby enabling the wireline tool to be deployed to a depth greater than the selected depth within the wellbore.  
   
   
       17 . The modular weight bar of  claim 1  where said engagement system comprises gravitationally resting said modular weight bar atop the downhole tool.  
   
   
       18 . The modular weight bar of  claim 1  further comprising a coaxial annular opening allowing for passage of a wireline therethrough.  
   
   
       19 . A method of deploying a modular weight bar for use with a downhole tool within a wellbore comprising the steps of: 
 disposing a downhole tool combined with a modular weight bar onto a wireline;    inserting said modular weight bar and the downhole tool within a wellbore opening;    lowering the combination within the wellbore to a depth within the wellbore;    separating the modular weight bar from the downhole tool and suspending the modular weight bar within the wellbore; and    lowering the downhole tool into the wellbore past the selected depth.    
   
   
       20 . The method of  claim 19  further comprising determining a selected depth within the wellbore such that the depth within the wellbore where said modular weight bar is separated from the downhole tool is substantially equal to the selected depth.  
   
   
       21 . The method of  claim 20  further comprising, forming at least one protrusion within the wellbore at approximately the selected depth.  
   
   
       22 . The method of  claim 21  further comprising adding at least one latch tab on said modular weight bar formed to mate with the at least one protrusion and secure and suspend the modular weight bar within the wellbore.  
   
   
       23 . The method of  claim 20  further comprising providing at least one slip to said modular weight bar, where the slip is activatable to secure and suspend the modular weight bar within the wellbore at approximately the selected depth.  
   
   
       24 . The method of  claim 19  further comprising raising the downhole tool from below the selected depth upward until the downhole tool recontacts the modular weight bar to reform a combination.  
   
   
       25 . The method of  claim 19  further comprising determining the total mass of the combination that is required to overcome wellbore pressure and providing sufficient mass to said modular weight bar so the mass of the combination is at least as great as the mass required to overcome wellbore pressure.