Patent ID: 7500787
Filing Date: 2009-03-10
Classification: E21B

Abstract:
1. A bearing assembly comprising: (a) a mandrel comprising an upper mandrel and a lower mandrel, wherein the lower mandrel is adapted for connection to a drill bit assembly and the upper mandrel is adapted for connection to a mud motor drive shaft; (b) a housing adapted for connection to a drill string, wherein the mandrel is telescopically disposed within the housing; (c) two seal assemblies consisting of an upper seal assembly and a lower seal assembly, forming a single sealed bearing chamber disposed between the mandrel and the housing; (d) a flow restrictor disposed between the mandrel and the housing, above the upper seal assembly; (e) an upper radial bearing disposed between the upper mandrel and the housing and a lower radial bearing disposed between the lower mandrel and the housing, wherein both upper and lower radial bearings are disposed within the single sealed bearing chamber; (f) an on-bottom thrust bearing stack bearing directly on the upper mandrel; and (g) an off-bottom thrust bearing, bearing directly on the upper mandrel.