Drill Bit Off-tip Cutters for Wear Resistance

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Solution Overview

Problem

Rotary drill bits face challenges in wear characteristics and rates of penetration, particularly when drilling challenging formations like conglomerates or chert, where polycrystalline diamond cutters are prone to damage and impregnated metal matrix materials offer lower penetration rates.

Innovation Solution

A drill bit design featuring polycrystalline diamond cutters on the leading edge and diamond impregnated cutting regions behind, with at least one off-tip cutting element that only engages the formation after initial wear, combining high initial penetration rates with extended durability through the use of metal matrix materials and powder metallurgy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If polycrystalline diamond cutters are used on the leading edge, then high rates of penetration are achieved, but the cutters are prone to damage and wear when drilling conglomerates or chert formations

Engineering Contradiction:

Improverate of penetrationVSAvoidwear resistance

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The cutting structure is segmented into distinct zones: polycrystalline diamond cutters on the leading edge for high penetration rates, and diamond impregnated cutting regions behind the leading edge for wear resistance. This segmentation allows each zone to perform its specialized function optimally.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The drill bit combines two different cutting materials with complementary properties: polycrystalline diamond for aggressive cutting and diamond impregnated metal matrix for durability. This composite approach leverages the strengths of both material types to resolve the contradiction between penetration rate and wear resistance.

Inventive Principle:

Principle #40Composite materials

2Reliability

If diamond impregnated metal matrix material is used in the bit body, then toughness and wear resistance are improved, but rates of penetration are reduced

Engineering Contradiction:

Improvewear resistanceVSAvoidrate of penetration

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

Different regions of the bit body are assigned different cutting properties: the leading edge uses polycrystalline diamond cutters for high penetration rates, while the regions behind the leading edge use diamond impregnated metal matrix for wear resistance. Each local region is optimized for its specific function.

Inventive Principle:

Principle #3Local quality

3Duration of action of moving object

If off-tip cutting elements are used that do not engage until bit wear occurs, then working life is extended, but initial penetration rate may be reduced

Engineering Contradiction:

Improveworking lifeVSAvoidinitial penetration rate

Core Design Contradiction:

Duration of action of moving objectVSProductivity

Solution Approach 1:

The off-tip cutting elements are positioned to engage the formation only after a predetermined amount of bit wear has occurred. This preliminary positioning protects the cutters during initial bit operation, and they automatically engage later to maintain penetration rates as the bit wears.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The engagement of cutting elements is made dynamic rather than static. The off-tip cutters transition from non-engaged to engaged state as the bit wears, allowing the cutting structure to adapt to the changing conditions during drilling operation.

Inventive Principle:

Principle #15Dynamics

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 design enhances the working life of the drill bit by protecting off-tip cutters from initial engagement, maintaining high penetration rates throughout its life, and offering improved durability due to the integration of diamond impregnated cutting regions, suitable for drilling difficult formations.

Implementation Method 1

diamond impregnated cutting regions, disposed behind the leading edge of the blade

Methodology Applied

Scientific EffectAbrasion: Abrasion

Implementation Method 2

cutting elements comprising polycrystalline diamond compacts (PDCs) and/or thermally stable polycrystalline (TSP) diamond are used to cut through a rock formation

Methodology Applied

Scientific EffectFracture: Fracture Mechanics

Data Source

PatentUS9869131B2Drill bit

Publication Date: 2018.01.16 NOV DOWNHOLE EURASIA LTD

AI summary

A drill bit comprises at least one blade, comprising a plurality of cutting elements in the form of polycrystalline diamond cutters disposed on a leading edge of the blade, at least one diamond impregnated cutting region, disposed behind the leading edge of the blade, and wherein at least one of the cutters disposed on the leading, edge is an off-tip cutting element, arranged so that it does not engage with the formation during drilling until bit wear has taken place.