Patent ID: 8833490
Filing Date: 2014-09-16
Classification: E21B

Abstract:
1. A drilling system comprising: a drive shaft having a fluid flow conduit extending therethrough; a drill bit mounted for rotation by the drive shaft and having a bit face which, in use, contacts a formation to be drilled, and having a fluid flow passage with an outlet near the center of the bit face; a baffle projecting from an outer periphery of the drive shaft, wherein an outer diameter of the baffle is less than an outer diameter of the drill bit; a first fluid flow line extending from the outside of the drive shaft to the flow passage in the drill bit, wherein the first fluid flow line is configured to direct fluid flowing down an annulus into the fluid flow passage of the drill bit; and a second fluid flow line extending from the outside of the drive shaft to the fluid flow conduit, wherein the second fluid flow line is configured to return fluid around the drill bit to the fluid flow conduit of the drive shaft, wherein the first fluid line has an inlet which is on an opposite side of the baffle to the drill bit, and the second fluid line has an inlet between the baffle and the drill bit.