Nanodiamond Coating for Downhole Drill Bit Voids

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Solution Overview

Problem

Downhole drilling tools with polycrystalline diamond cutting elements face issues due to catalysts used in their manufacture, which can enhance the transition of diamond to graphite at lower temperatures and cause thermal expansion mismatch, leading to reduced thermal conductivity and integrity concerns.

Innovation Solution

A coating is applied using chemical vapor deposition (CVD), plasma-activated vapor deposition (PAVD), or other deposition methods to fill voids created by catalyst removal, comprising a binder layer and diamond nanoparticles in a matrix, or a pure diamond layer, enhancing thermal conductivity and hardness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If catalysts are used in the manufacture of polycrystalline diamond cutting elements, then the diamond particles can be bonded together to form a cohesive structure, but the catalysts enhance the transition of diamond to graphite at lower temperatures and cause thermal expansion mismatch

Engineering Contradiction:

Improvecohesive structureVSAvoidthermal stability

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The patent removes catalysts from the polycrystalline diamond cutting elements through leaching processes (acid treatment) to eliminate the harmful thermal effects while retaining the beneficial cohesive structure. This extraction of the problematic catalyst material resolves the contradiction by eliminating the source of thermal instability.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the thermal parameters of the cutting element by replacing catalyst-containing diamond structures with catalyst-free structures through leaching and re-coating processes. This parameter change eliminates the thermal expansion mismatch and graphite transition issues while maintaining structural integrity.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If catalysts are removed from the cutting elements, then thermal conductivity and integrity are improved, but voids are created in the diamond table structure

Engineering Contradiction:

Improvethermal conductivityVSAvoidstructural integrity

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent applies different treatments to different regions of the cutting element. The diamond table is leached to remove catalysts and improve thermal conductivity, while the binder layer is engineered to fill the resulting voids and maintain structural integrity. This localized quality differentiation resolves the contradiction between thermal performance and structural stability.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent introduces a binder layer as an intermediary material that fills the voids created by catalyst removal. This binder layer acts as a mediator that maintains structural integrity while allowing the underlying diamond table to achieve improved thermal conductivity through catalyst removal.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If a coating is applied to fill voids and enhance hardness, then abrasion resistance and thermal conductivity are improved, but the device complexity and manufacturing process are increased

Engineering Contradiction:

Improveabrasion resistanceVSAvoidmanufacturing process

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent creates a composite structure consisting of a leached diamond table, a binder layer, and an outer coating layer. This composite material approach fills voids and enhances hardness while improving abrasion resistance and thermal conductivity. The multiple-layer composite structure resolves the performance benefits while integrating the complexity into a systematic manufacturing process.

Inventive Principle:

Principle #40Composite materials

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 coating increases the hardness of cutting elements by up to 50% and abrasion resistance by at least 40%, improving thermal conductivity and overall toughness, while shielding against hazardous materials and extending the lifespan of the cutting elements.

Implementation Method 1

A coating is applied using chemical vapor deposition (CVD), plasma-activated vapor deposition (PAVD), or other deposition methods to fill voids created by catalyst removal

Methodology Applied

Scientific EffectChemical vapor deposition: Chemical Vapour Deposition

Implementation Method 2

A coating is applied using chemical vapor deposition (CVD), plasma-activated vapor deposition (PAVD), or other deposition methods to fill voids created by catalyst removal

Methodology Applied

Scientific EffectCondensation: Condensation

Data Source

PatentEP3374541B1Downhole drill bit with a cutting element coated with a nanodiamond polycrystalline containing coating

Publication Date: 2023.11.29 NAT OILWELL DHT LP

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Figure 2A~2B
Figure 3A~3B

AI summary

Systems and methods discussed herein are related to a coating for a diamond table for a cutting element that may be used in downhole tooling. The coating is employed to fill a plurality of voids left by the manufacturing process that compromise the integrity of the cutting element and the associated downhole tooling. The coating may comprise diamond nanoparticles in a metal matrix and may be used with or without a binder layer applied directly to the diamond table, the coating may alternatively be a pure diamond film coating, and may be employed to fill voids left by the manufacturing process.