Drill Bit Blade Face Segmentation for Rubbing Control
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Solution Overview
Problem
Existing drill bits face challenges in controlling contact and rubbing area during subterranean drilling, particularly in off-center drilling operations, which can lead to increased rubbing forces and potential damage to the formation, and existing depth-of-cut control features may not adequately manage these forces without exceeding the compressive strength of the rock.
Innovation Solution
The design incorporates a sweep zone on the blade face surface of the drill bit, which rotationally trails the contact zone, reducing the surface area in contact with the formation and enhancing rubbing control by maintaining the desired depth-of-cut and cutter profile, thereby controlling the pressure and stability during drilling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the drill bit uses traditional depth-of-cut control features, then the cutting performance is maintained, but the rubbing forces increase and may exceed the compressive strength of the formation rock
Solution Approach 1:
The blade face surface is segmented into distinct functional zones: a contact zone for primary cutting and weight-bearing, and a sweep zone for stability and rubbing control. This segmentation allows the drill bit to manage rubbing forces by confining contact to specific areas rather than the entire blade face, preventing excessive forces that would exceed formation rock compressive strength.
Solution Approach 2:
Different regions of the blade face surface are assigned different functional qualities. The contact zone has properties optimized for cutting and bearing axial load, while the sweep zone has properties optimized for stability and controlling rubbing forces. This local differentiation allows the drill bit to maintain effective cutting performance while limiting rubbing forces to acceptable levels.
2Stability of the object's composition
If the drill bit increases contact area with the formation, then stability improves, but rubbing forces increase and may damage the formation
Solution Approach 1:
The blade face surface is divided into a contact zone and a sweep zone. The sweep zone provides additional stability through controlled contact with the formation wall, while the contact zone maintains the primary cutting function. This segmentation allows stability enhancement without proportionally increasing harmful rubbing forces across the entire blade face.
Solution Approach 2:
The sweep zone is designed with specific geometric properties that provide stability through light contact with the formation wall, while the contact zone maintains properties optimized for cutting. This local quality differentiation allows the drill bit to gain stability benefits without subjecting the formation to excessive rubbing forces that would cause damage.
3Object-affected harmful factors
If the drill bit reduces rubbing area, then formation damage is prevented, but depth-of-cut control becomes less effective
Solution Approach 1:
By segmenting the blade face surface into contact and sweep zones, the invention concentrates the depth-of-cut control function in the contact zone while using the sweep zone for stability. This allows reduction of the total rubbing area (by excluding the sweep zone from primary cutting contact) while maintaining effective depth-of-cut control through the optimized contact zone geometry.
Solution Approach 2:
The contact zone is designed with specific geometric properties that provide effective depth-of-cut control, while the sweep zone provides stability with minimal rubbing. This local quality assignment allows the system to reduce overall rubbing area and prevent formation damage while maintaining precise depth-of-cut control through the specially designed contact zone.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution allows for improved stability and reduced propensity for lateral movement and whirl, while maintaining effective cutting performance by controlling the rubbing area and pressure distribution, thus enhancing drilling efficiency and preventing damage to the formation.
Implementation Method 1
The sweep zone may rotationally trail the contact zone with respect to a direction of intended bit rotation about the longitudinal axis of the bit body
Data Source
AI summary
Drill bits for subterranean drilling comprising a bit body including at least one blade that includes a blade face comprising a contact zone and a sweep zone are disclosed. In particular, drill bits including at least one blade that extends at least partially over a nose region of the bit body, a shoulder region of the bit body and a gage region of the bit body and that include a sweep zone that rotationally trails the contact zone with respect to a direction of intended bit rotation about a longitudinal axis of the bit body and include a contact zone that defines a range of about 90% to about 30% of the blade face surface area is disclosed. Additionally, drill bits comprising a sweep zone located at least partially within a gage region are disclosed. Also, methods of off-center drilling and methods of manufacturing drill bits are disclosed.