US 6,981,561 B2
Downhole cutting mill
Sven Krueger, Winsen/Aller (Germany); Volker Krueger, Celle (Germany); Harald Grimmer, Lachendorf (Germany); Joerg Christanseen, Winsen/Aller (Germany); and Volker Peters, Wienhausen (Germany)
Assigned to Baker Hughes Incorporated, Houston, Tex. (US)
Filed on Sep. 02, 2003, as Appl. No. 10/653,334.
Application 10/653334 is a continuation in part of application No. 10/251138, filed on Sep. 20, 2002, abandoned.
Claims priority of provisional application 60/323803, filed on Sep. 20, 2001.
Prior Publication US 2004/0112642 A1, Jun. 17, 2004
Int. Cl. E21B 21/00 (2006.01)
U.S. Cl. 175—312 34 Claims
OG exemplary drawing
 
1. An apparatus for reducing the size of particles entrained in a drilling fluid returning up a wellbore, comprising:
(a) a housing disposed in a wellbore upstream of a selected wellbore device, an inlet in fluid communication with the return fluid, an exit for directing the return fluid to said selected wellbore device, and a first stage including:
(i) at least one cutting surface formed in a chamber formed in said housing; and
(ii) a cutting head disposed in said chamber, said cutting head cooperating with said at least one cutting surface to reduce the size of the particles entrained in the drilling fluid to a predetermined size.