Drillable Bit Nozzle Retainer with Interchangeable Nozzle Capability

Abstract

A drillable bit nozzle assembly can be used on a casing drilling bit and features a support housing preferably of the same material as the bit crown. The housing is preferably attached by welding and contains a groove for a seal and internal threads for an insert retainer. A landing shoulder for the hardened inserts allows different sizes to be inserted in the housing and retained by a hardened or carbide ring holder that engages the internal threads. The insert and the retainer are sufficiently thin walled to break during mill out while the housing is softer and easily milled out.

1 . A downhole drill bit with a drillable nozzle assembly, comprising:
 a body having at least one passage;   at least one nozzle housing in said passage, said housing accepting one of a plurality of nozzle bodies that have differing flow paths therethrough.   
   
   
       2 . The bit of  claim 1 , wherein:
 said nozzle housing is made of a softer material than said nozzle body.   
   
   
       3 . The bit of  claim 1 , wherein:
 said nozzle housing is welded to said passage   
   
   
       4 . The bit of  claim 1 , wherein:
 said passage comprises a landing shoulder and said nozzle housing has a radial surface that lands on said shoulder to locate said nozzle housing in said passage.   
   
   
       5 . The bit of  claim 1 , wherein:
 said nozzle housing further comprises an internal landing shoulder;   said nozzle bodies are all adapted to land on said shoulder.   
   
   
       6 . The bit of  claim 5 , further comprising:
 a retainer removably mounted within said nozzle housing to secure a nozzle body to said shoulder.   
   
   
       7 . The bit of  claim 6 , wherein:
 said retainer is made of the same material as said nozzle body.   
   
   
       8 . The bit of  claim 6 , wherein:
 said retainer is held by threads.   
   
   
       9 . The bit of  claim 6 , further comprising:
 an outlet opening in said nozzle housing, all of said nozzle bodies configured to extend through said outlet opening when landed on said shoulder;   a seal between said mounted nozzle body and said nozzle housing.   
   
   
       10 . The bit of  claim 6 , wherein:
 said nozzle bodies comprise an exterior flange located on an end thereof having an outer dimension that allows landing on said shoulder.   
   
   
       11 . The bit of  claim 10 , wherein:
 said retainer and said nozzle bodies are made of carbide.   
   
   
       12 . The bit of  claim 1 , wherein:
 said nozzle body is held to said nozzle housing by an interference fit.   
   
   
       13 . The bit of  claim 1 , wherein:
 said nozzle housing is held to said body by an interference fit.   
   
   
       14 . The bit of  claim 6 , wherein:
 said retainer is held to said nozzle housing by an interference fit.   
   
   
       15 . The bit of  claim 6 , wherein:
 said retainer comprises a ring shape with a through passage aligned with the flow path of a nozzle body that it secures.   
   
   
       16 . The bit of  claim 15 , wherein:
 said ring has an exterior thread for engagement to said nozzle housing.   
   
   
       17 . The bit of  claim 15 , wherein:
 said ring is retained to said nozzle housing with a snap ring.   
   
   
       18 . The bit of  claim 15 , wherein:
 said ring is retained to said nozzle housing with a pin and slot assembly.