Drilling and hole enlargement device
AssigneeSmith International, Inc.
InventorsJohn Campbell, Charles Dewey, Lance Underwood, Ronald Schmidt
Life of this patent
Estimating the term…
Abstract
An expandable drilling apparatus is deployed upon a distal end of a drillstring and includes a cutting head and a substantially tubular main body adjacent the cutting head providing a plurality of axial recesses configured to receive arm assemblies configured to translate between a retracted and an extended position. A flow switch actuates the arm assemblies when a drilling fluid pressure exceeds an activation value and the drilling apparatus includes a biasing member to reset the arm assemblies when the drilling fluid pressure falls below a reset value.
Claims48
An expandable drilling apparatus deployed upon a distal end of a drillstring and configured to drill a formation, the expandable drilling apparatus comprising:
- a cutting head to drill the formation;
- a substantially tubular main body adjacent the cutting head, the main body providing at least one axial recess configured to receive an arm assembly;
- the arm assembly configured to translate between a retracted position and an extended position;
- a flow switch to actuate the arm assembly between the retracted and extended positions;
- wherein the arm assemblies are configured to extend when a drilling fluid pressure exceeds an activation value;
- and
- a biasing member configured to reset the arm assembly into the retracted position when the drilling fluid pressure falls below a reset value.
An expandable drilling apparatus connected to a drillstring, the drilling apparatus comprising:
- a cutting head disposed upon a distal end of a substantially tubular main body;
- the main body providing a plurality of axial recesses adjacent to the cutting head;
- a plurality of arm assemblies retained within the axial recesses, wherein the arm assemblies are configured to translate from a retracted position to an extended position along a plurality of grooves formed into walls of the axial recesses;
- a piston configured to thrust the arm assemblies into the extended position when a pressure of fluids flowing through the drillstring is increased;
- and
- the arm assemblies comprising stabilizer pads upstream from and adjacent to underreamer cutters.
A switch to divert drilling fluids from a bore of a downhole apparatus, the switch comprising:
- the bore providing an aperture in communication with a device to be activated;
- a flow tube slidably engaged within the bore isolating the aperture from the drilling fluids when in a deactivated position;
- the aperture in communication with drilling fluids in the bore when the flow tube is in an activated position;
- a biasing member extending between the flow tube and a spring retainer within the bore, the biasing member configured to bias the flow tube into the deactivated position;
- a nozzle disposed within the flow tube, the nozzle configured to transmit a force to the flow tube corresponding to a pressure of drilling fluids flowing therethrough;
- and
- the force displacing the flow tube into the activated position when the pressure of the drilling fluids flowing therethrough exceed an activation value.
The switch of claim 41, wherein the piston is configured to retract when the pressure of the drilling fluids flowing through the bore of the downhole apparatus falls below a reset value.
A method of drilling a borehole comprising:
- disposing a drilling assembly having expandable arm assemblies adjacent to a cutting head upon a distal end of a drillstring;
- drilling a pilot bore with the cutting head with the expandable arm assemblies in a retracted position;
- increasing pressure of drilling fluids within the drilling assembly to expand the expandable arm assemblies;
- underreaming the pilot bore with cutting elements of the expandable arm assemblies;
- stabilizing the drilling assembly with stabilizer pads of the expandable arm assemblies.
Dependencies are inferred from the claim text.