Hybrid Rolling Cone Drill Bit Teeth and Inserts

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Solution Overview

Problem

Existing earth-boring drill bits struggle to maintain a high rate of penetration and durability when drilling through formations with both soft and hard zones, often requiring frequent bit replacements, which is time-consuming and costly.

Innovation Solution

A rolling cone drill bit design featuring a combination of teeth and inserts, where the inserts are positioned within the teeth and secured to the cone body, allowing for effective cutting in both soft and hard formations without the need for bit swapping, utilizing a molding method to form the cone cutter with metal powder and sintering process to integrate the inserts and teeth monolithically.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If milled teeth are used for cutting, then the cutting surface area is large and effective in softer formations, but the teeth erode and wear rapidly when engaging harder formations

Engineering Contradiction:

Improverate of penetrationVSAvoiddurability in hard formations

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent applies local quality by providing different cutting elements (milled teeth and inserts) at different locations on the cone cutter. The milled teeth provide large cutting surfaces for soft formations, while hard inserts provide durability for hard formations. This spatial differentiation of cutting element properties resolves the contradiction between productivity in soft formations and reliability in hard formations.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent uses composite materials by combining milled tooth structures with inserted hard material elements. The hybrid cutting structure integrates the advantages of both milled teeth (large surface area) and inserts (hardness and durability), allowing the bit to effectively cut both soft and hard formations without rapid wear.

Inventive Principle:

Principle #40Composite materials

2Reliability

If tungsten carbide inserts are used for cutting, then the durability is high in harder formations, but the cutting surfaces are smaller reducing effectiveness in softer formations

Engineering Contradiction:

Improvedurability in hard formationsVSAvoidrate of penetration in soft formations

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent positions inserts and milled teeth in specific locations on the cone cutter surface. Milled teeth are provided in areas where large cutting surfaces are beneficial for soft formations, while inserts are positioned for durability in hard formation zones. This local differentiation resolves the contradiction between reliability and productivity across different formation types.

Inventive Principle:

Principle #3Local quality

3Device complexity

If a single type of cutting element is used, then the bit design is simple, but the bit requires frequent replacements when drilling through varied formations

Engineering Contradiction:

Improvecutting structure designVSAvoidbit lifespan

Core Design Contradiction:

Device complexityVSDuration of action of moving object

Solution Approach 1:

The patent creates a universal cutting structure that can handle multiple formation types with a single bit design. By integrating both milled teeth and inserts on the same cone cutter, the bit becomes multi-functional, capable of effectively drilling through both soft and hard formations without requiring bit replacement. This resolves the contradiction between design simplicity and extended bit lifespan.

Inventive Principle:

Principle #6Universality (Multi-functionality)

4Productivity

If the drill bit is replaced frequently to maintain drilling efficiency, then the drilling speed is optimized for current formation, but the operational time and cost increase due to tripping the drill string

Engineering Contradiction:

Improvedrilling speedVSAvoidtime for bit replacement

Core Design Contradiction:

ProductivityVSLoss of time

Solution Approach 1:

The hybrid cutting structure enables continuous drilling through varied formations without requiring bit replacement. The combination of milled teeth and inserts allows the bit to maintain effective cutting action across different formation hardnesses, eliminating interruptions and trips. This resolves the contradiction between maintaining optimal drilling speed and minimizing time loss from bit replacement.

Inventive Principle:

Principle #20Continuity of useful action

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

The hybrid bit design enhances drilling efficiency by maintaining a high rate of penetration and extending the drill bit's lifespan, enabling continuous drilling through varied formations without the need for frequent replacements, thus reducing operational costs and time.

Implementation Method 1

utilizing a molding method to form the cone cutter with metal powder and sintering process to integrate the inserts and teeth monolithically

Methodology Applied

Scientific EffectSintering: Sintering

Data Source

PatentUS9249628B2Hybrid rolling cone drill bits and methods for manufacturing same

Publication Date: 2016.02.02 NAT OILWELL DHT LP

AI summary

A rolling cone drill bit for drilling a borehole in earthen formations includes a bit body having a bit axis. In addition, the rolling cone drill bit includes a rolling cone cutter mounted on the bit body and having a cone axis of rotation. The cone cutter includes a cone body, a plurality of teeth arranged in a first inner row, and a plurality of inserts. Each insert is disposed within one tooth in the first inner row.