Patent ID: 9121226
Filing Date: 2015-09-01
Classification: E21B

Abstract:
1. A method of hydraulically activating a near-bit reamer, said method comprising: providing a near-bit reamer including a grate assembly including a sloped top surface with a series of guide slots and an opening; positioning the near-bit reamer upstream of one or more drill bit nozzle inlets of a drill bit positioned in a bottom hole assembly, said opening of the grate assembly providing access to the drill bit nozzle inlets, and said opening being located proximal to a wall of a central fluid passage in the drill bit: lowering the bottom hole assembly into a wellbore; holding cutter elements of the near-bit-reamer in an unactivated position using at least one shear pin; inserting one or more drop balls into a drilling fluid; flowing the drilling fluid and the drop balls to the grate assembly upstream of the one or more drill bit nozzle inlets; guiding the drop balls through the opening towards the drill bit nozzle inlets with the grate assembly; at least partially plugging one or more of the drill bit nozzle inlets with the drop balls thereby restricting fluid flow and correspondingly increasing hydraulic pressure of the drilling fluid; creating a force on the at least one shear pin responsive to the hydraulic pressure, to shear the at least one shear pin, thereby moving the cutter elements to an activated radially-outward position.