Magnetic Depth of Cut Controller for Drill Bits

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Solution Overview

Problem

Conventional fixed-cutter drill bits face challenges in managing varying compressive strengths of subterranean formations, leading to issues like stick-slip and reduced drilling efficiency due to inconsistent depth of cut and excessive force on cutters.

Innovation Solution

The implementation of a depth of cut controller (DOCC) with a depth of cut element that extends or retracts in response to external forces, utilizing a magnetic fluid and magnetic field to provide variable resistance and control the depth of cut, thereby adapting to changing formation strengths.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a fixed-cutter drill bit is used with conventional depth of cut control, then the drill bit can maintain a consistent depth of cut, but it cannot adapt to varying compressive strengths of subterranean formations, leading to stick-slip and reduced drilling efficiency

Engineering Contradiction:

Improveadaptability to varying formation compressive strengthVSAvoiddrilling efficiency and stability

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The depth of cut controller employs a movable DOC element that can dynamically extend or retract in response to external forces applied by the formation. This dynamic adjustment allows the system to adapt to varying compressive strengths of subterranean formations, preventing stick-slip and maintaining reliable drilling operation.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The DOC element responds to external forces from the formation, creating a feedback mechanism where the depth of cut is automatically adjusted based on real-time formation resistance. This feedback loop ensures the drill bit adapts to changing formation conditions, maintaining optimal drilling efficiency.

Inventive Principle:

Principle #23Feedback

2Productivity

If the depth of cut is increased to improve drilling speed, then productivity increases, but the risk of stick-slip and damage to the drill bit increases

Engineering Contradiction:

Improvedrilling speedVSAvoidstick-slip and damage risk

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The DOC element dynamically adjusts its position based on external forces, allowing the system to operate at higher productivity levels while automatically reducing depth of cut when resistance increases, thereby preventing stick-slip and damage.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The movable DOC element acts as a cushioning mechanism that prevents excessive forces from reaching the cutters by automatically reducing depth of cut before damage can occur, protecting the drill bit while maintaining high drilling speed.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

3Adaptability or versatility

If a movable depth of cut controller is implemented, then adaptability to formation changes is improved, but the device complexity increases

Engineering Contradiction:

Improvedynamic depth of cut adjustmentVSAvoidstructure of depth of cut controller

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The DOC element is designed to be self-regulating, automatically responding to external forces without requiring complex external control systems. The simplicity of this self-service mechanism reduces overall device complexity while maintaining high adaptability.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The depth of cut control function is extracted as a separate, simple movable element that can be independently adjusted, simplifying the overall controller structure while maintaining dynamic adaptability to formation conditions.

Inventive Principle:

Principle #2Taking out (Extraction)

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 effectively reduces the risk of stick-slip and other damage-causing conditions, enhancing drilling efficiency by dynamically adjusting the depth of cut and resistance to match the formation's compressive strength, thus protecting the drill bit and improving operational efficiency.

Implementation Method 1

a magnetic fluid disposed within the bore of the housing between the DOC element and the second end of the housing, the magnetic fluid having a viscosity that changes responsive to proximity to the magnet to provide a variable resistance to movement of the DOC element

Methodology Applied

Scientific EffectMagnetic field effect on magnetic fluid viscosity: Magnetorheological Fluid

Data Source

PatentUS11199052B2Magnetic depth of cut control

Publication Date: 2021.12.14 HALLIBURTON ENERGY SERVICES INC

AI summary

A magnetic depth of cut controller (DOCC) includes a housing having a body portion with a bore extending into the body portion and a depth of cut (DOC) element positioned at least partially within the bore and having a working face to engage a subterranean formation. The DOC element is moveable within the bore to extend or retract from a first end of the housing. Further, the DOCC includes a magnet secured within the bore of the housing between the DOC element and a second end of the housing. Moreover, the DOCC includes a magnetic fluid disposed within the bore of the housing between the DOC element and the second end of the housing. The magnetic fluid has a viscosity that changes responsive to proximity to the magnet to provide a variable resistance to movement of the DOC element.