Methods for optimizing and balancing roller-cone bits
AssigneeHalliburton Energy Services, Inc.
InventorShilin Chen
Life of this patent
Estimating the term…
Abstract
Roller cone drilling wherein the bit optimization process equalizes the downforce (axial force) for the cones (as nearly as possible, subject to other design constraints). Bit performance is significantly enhanced by equalizing downforce.
Claims13
A roller cone drill bit comprising:
- a plurality of arms;
- rotatable cutting structures mounted on respective ones of said arms;
- and
- a plurality of teeth located on each of said cutting structures;
- wherein approximately the same axial force is acting on each of said cutting structure.
A roller cone drill bit comprising:
- a plurality of arms;
- rotatable cutting structures mounted on respective ones of said arms;
- and
- a plurality of teeth located on each of said cutting structures;
- wherein a substantially equal volume of formation is drilled by each said cutting structure.
A rotary drilling system, comprising:
- a drill string which is connected to conduct drilling fluid from a surface location to a rotary drill bit;
- a rotary drive which rotates at least part of said drill string together with said bit
- said rotary drill bit comprising
- a plurality of arms;
- rotatable cutting structures mounted on respective ones of said arms;
- and
- a plurality of teeth located on each of said cutting structures;
- wherein approximately the same axial force is acting on each of said cutting structure.
A method of designing a roller cone drill bit, comprising the steps of:
- (a) calculating the volume of formation cut by each tooth on each cutting structure;
- (b) calculating the volume of formation cut by each cutting structure per revolution of the drill bit;
- (c) comparing the volume of formation cut by each of said cutting structures with the volume of formation cut by all others of said cutting structures of the bit;
- (d) adjusting at least one geometric parameter on the design of at least one cutting structure;
- and
- (e) repeating steps (a) through (d) until substantially the same volume of formation is cut by each of said cutting structures of said bit.
A method of designing a roller cone drill bit, the steps of comprising:
- (a) calculating the axial force acting on each tooth on each cutting structure;
- (b) calculating the axial force acting on each cutting structure revolution of the drill bit;
- (c) comparing the axial force acting on each of said cutting structures with the axial force on the other ones of said cutting structures of the bit;
- (d) adjusting at least one geometric parameter on the design of at least one cutting structure;
- (e) repeating steps (a) through (d) until approximately the same axial force is acting on each cutting structure.
A method of designing a roller cone drill bit, the steps of comprising:
- (a) calculating the force balance conditions of a bit;
- (b) defining design variables;
- (c) determine lower and upper bounds for the design variables;
- (d) defining objective functions;
- (e) defining constraint functions;
- (f) performing an optimization means;
- and,
- (g) evaluating an optimized cutting structure by modeling.
A method of using a roller cone drill bit, comprising the step of rotating said roller cone drill bit such that substantially the same volume of formation is cut by each roller cone of said bit.
A method of using a roller cone drill bit, comprising the step of rotating said roller cone drill bit such that substantially the same axial force is acting on each roller cone of said bit.
Dependencies are inferred from the claim text.