Reduced flow milling

Abstract

Methods and apparatus to reduce flow in front of the drill bit while milling improve milling debris size. Reducing flow on the drill bit face while milling allows the drill cuttings to remain at the drilling surface longer and reduce the size of the cuttings. The smaller cuttings increase the ease and speed of cutting removal.

1 . A process for milling a wellbore plug where the process comprises:
 a) a drillstring comprising:
 a drilling motor, drillstring pipe, a crossover, and a drill bit, 
   b) rotating the drillstring and drillbit;   c) circulating a drill fluid through said drillstring, and   d) partially or fully diverting the drilling fluid after the drilling motor before reaching the face of the drillbit.   
     
     
         2 . The method of  claim 1  wherein said drilling fluid is diverted with a blind crossover. 
     
     
         3 . The method of  claim 1  wherein said drilling fluid is diverted within a drill bit reducing or preventing flow to the face of the drillbit. 
     
     
         4 . The method of  claim 1  wherein said plug is a composite plug, cement plug, cast iron plug, alloy plug, or a combination thereof. 
     
     
         5 . A drilling fluid crossover comprising:
 a) a male thread for coupling drillstring pipe,   b) a female thread for coupling a drill bit, and   c) a full or partial diverter blocking forward flow of the drilling fluid through the drillbit, and   d) one or more ports for releasing the drilling fluid.   
     
     
         6 . The drilling fluid crossover of  claim 5  wherein said drilling fluid is diverted through one or more side ports. 
     
     
         7 . The blind crossover of  claim 5  wherein said drilling fluid is partially diverted through one or more side ports. 
     
     
         8 . The blind crossover of  claim 5  wherein said drilling fluid is equally diverted through two or more side ports of equal size spaced at equal distances around the blind crossover. 
     
     
         9 . A drill bit comprising:
 a) a male thread for coupling a drillstring,   b) one or more ports located on the side of the drill bit, and   c) cutting surface for milling a wellbore plug   wherein said bit diverts drilling fluid flow before reaching the drill bit face.   
     
     
         10 . The drill bit of  claim 9  wherein said drilling fluid is diverted through one or more side ports. 
     
     
         11 . The drill bit of  claim 9  wherein said drilling fluid is partially diverted through one or more side ports. 
     
     
         12 . The drill bit of  claim 9  wherein said drilling fluid is equally diverted through one or more side ports of equal size spaced at equal distances around the blind crossover.