Method and apparatus for preventing the friction induced rotation of non-rotating stabilizers

Abstract

A method and apparatus prevents rotation of a stabilizer which rotates due to friction-induced forces of bearing seals disposed in a shaft. The apparatus includes a stabilizer having a ridged edge where the stabilizer is mounted to a drilling tool using a deformable member. The deformable member assists in creating friction of the stabilizer edge against a drilled bore hole wall and thereby reduces friction-induced rotation.

1 . A stabilizer assembly mountable on a surface of a drilling tool having a longitudinal shaft, said stabilizer comprising: 
 a plurality of stabilizer blades, each blade having multiple ridges and being independently mounted on the drilling tool.    
   
   
       2 . The stabilizer assembly according to  claim 1 , further comprising a displacement member disposed between each stabilizer blade and the drilling tool, said displacement member deformable to provide a minimum radius and a maximum radius, different from the minimum radius, from a center of the longitudinal shaft to an outer extremity of at least one of the multiple ridges.  
   
   
       3 . The stabilizer assembly according to  claim 2 , wherein when the displacement member provides the minimum radius, at least one of the multiple ridges are exposed.  
   
   
       4 . The stabilizer assembly according to  claim 2 , wherein the displacement member comprises a load spring.  
   
   
       5 . The stabilizer assembly according to  claim 4 , wherein the load spring provides a rotational resistance RR sufficient to counterbalance frictional rotation RDT according to an expression:  
     
       
         
           
             RDT 
             = 
             
               
                 
                   bd 
                   · 
                   ff 
                   · 
                   SBF 
                 
                 2 
               
               + 
               
                 2 
                 · 
                 st 
               
             
           
         
       
     
     where:  
     
       
         
               
               
               
             
                   
                   
               
                   
                   
               
                   
                 RDT = rotational driving torque 
                 in lbs. 
               
                   
                 bd = shaft bearing diameter 
                 in. 
               
                   
                 ff = bearing friction factor 
                 * 
               
                   
                 SBF = sum of all the bearing forces 
                 lbs. 
               
                   
                 st = rotating seal torque 
                 in lbs. 
               
                   
                   
               
                   
                   
               
           
              
              
             
             
              
              
              
              
              
              
              
             
          
         
       
     
   
   
       6 . The stabilizer assembly according to  claim 4 , wherein the load spring has a spring load in a range of 50-60 lbs across a travel distance of ⅛ inch.  
   
   
       7 . A stabilizer assembly mountable on a surface of a drilling tool having a longitudinal shaft, said stabilizer comprising: 
 at least a first stabilizer blade having multiple ridges and movably mounted on the drilling tool.    
   
   
       8 . The stabilizer assembly according to  claim 7 , wherein the stabilizer assembly includes a second stabilizer blade having multiple ridges, said second stabilizer blade independently and movably mounted onto the drilling tool from the first stabilizer blade.  
   
   
       9 . The stabilizer assembly according to  claim 8 , wherein each of the first and second stabilizer blades is attached to the drilling tool by a displacement member disposed between the stabilizer blade and the drilling tool, said displacement member deformable to provide a minimum radius and a maximum radius from a center of the longitudinal shaft to an outer extremity of at least one of the multiple ridges.  
   
   
       10 . The stabilizer assembly according to  claim 9 , wherein when the displacement member provides the minimum radius, at least one of the multiple ridges are exposed.  
   
   
       11 . The stabilizer assembly according to  claim 9 , wherein the displacement member comprises a load spring.  
   
   
       12 . The stabilizer according to  claim 11 , wherein the load spring provides a rotational resistance RR sufficient to counterbalance frictional rotation FR according to an expression: This equation must be replaced by equation 3  
     
       
         
           
             
               RT 
               s 
             
             = 
             
               
                 sd 
                 2 
               
               ⁢ 
               
                 ( 
                 
                   FS 
                   + 
                   
                     Σ 
                     ⁢ 
                     
                         
                     
                     ⁢ 
                     F 
                     ⁢ 
                     
                         
                     
                     ⁢ 
                     spring 
                   
                 
                 ) 
               
               ⁢ 
               
                 ( 
                 0.63 
                 ) 
               
               ⁢ 
               
                 ( 
                 0.9 
                 ) 
               
             
           
         
       
     
     where:  
     
       
         
               
               
             
                   
               
                   
               
                 RTs = rotation resisting torque with spring loaded contacts 
                 in lbs. 
               
                 FS = total lateral loads on all of the stabilizer blades 
                 lbs. 
               
                 sd = stabilizer diameter 
                 in. 
               
                 ΣFspring = sum of all of the spring forces 
                 lbs 
               
                   
               
                   
               
           
              
              
             
             
              
              
              
              
              
              
             
          
         
       
     
   
   
       13 . The stabilizer according to  claim 11 , wherein the load spring has a spring load in a range of 50-60 lbs across a travel distance of ⅛ inch.  
   
   
       14 . A method of forming a stabilizer assembly for a drilling tool including a plural number of bearings disposed in a longitudinal shaft, said method comprising: 
 determining a lateral force of each plural number of bearings SBF;    determining a shaft bearing diameter bd;    determining a frictional seal torque st;    determining a bearing friction factor ff;    and determining a resistance torque RTs for the stabilizer sufficient to counterbalance a frictional rotation RDT according to an expression:              RT   s     =       sd   2     ⁢     (     FS   +     Σ   ⁢           ⁢   F   ⁢           ⁢   spring       )     ⁢     (   0.63   )     ⁢     (   0.9   )               where:                                RTs = rotation resisting torque with spring loaded contacts   in lbs.     FS = total lateral loads on all of the stabilizer blades   lbs.     sd = stabilizer diameter   in.     ΣFspring = sum of all of the spring forces   lbs.