Drilling and hole enlargement device
AssigneeSmith International, Inc.
InventorsJohn E. Campbell, Charles H. Dewey, Lance D. Underwood, Ronald G. 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.
Claims41
An expandable drilling apparatus deployed upon a distal end of a drilistring 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 integral within the main body 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 a flow switch integral within the main body is increased;
- and
- the arm assemblies comprising stabilizer pads upstream from and adjacent to underreamer cutters.
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 cuffing head with the expandable arm assemblies in a retracted position;
- increasing pressure of drilling fluids and activating a flow switch integral within a main body of 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.
The method of claim 36, further comprising activating a switch of claim 39 to expand the expandable arm assemblies.
Dependencies are inferred from the claim text.