Ridged PCD Cutting Element for Drill Bit Durability

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Solution Overview

Problem

Current drill bits with polycrystalline diamond (PCD) cutting elements face challenges in durability and rate of penetration (ROP), leading to frequent bit changes and increased drilling costs due to manufacturing complexities and limited longevity.

Innovation Solution

The design incorporates a cutting element with a PCD layer featuring an elongate ridge and a continuously curved surrounding surface, including side regions and a ramp region, which concentrates force and directs drilling fluid for enhanced cutting efficiency and durability, while varying the PCD layer thickness and angles to optimize performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a standard PCD cutting element is used, then the drilling process is simple, but the durability and ROP are insufficient leading to frequent bit changes

Engineering Contradiction:
ImprovedurabilityVSAvoidcutting element design complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The cutting element is divided into distinct functional zones: a land portion for structural support, a ramp portion for material engagement and extrudate direction, and a cutting face with a ridge for active cutting. This segmentation allows each zone to be optimized for its specific function, improving overall durability and ROP while maintaining manufacturability through defined geometric boundaries

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention transitions from a conventional flat cutting face to a three-dimensional structured surface featuring a raised ridge and inclined ramp. This dimensional change creates additional functional surfaces that direct extrudate away from the cutting face and concentrate cutting forces, thereby enhancing durability and rate of penetration without excessive complexity

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Productivity

If a standard PCD cutting element is used, then manufacturing is simple, but the ROP and cutting efficiency are limited

Engineering Contradiction:
ImproveROPVSAvoidcutting element structure
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The cutting element incorporates curved surfaces including a ramp portion with an inclined angle and a cutting face with a ridge that creates curved extrudate flow paths. These curved geometries optimize material removal by directing chips away from the cutting zone and concentrating cutting forces, thereby enhancing ROP while maintaining reasonable manufacturing complexity

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The invention optimizes specific geometric parameters including the ramp angle (providing an inclined surface between 10-45 degrees), ridge height (0.1-0.5 times the cutting element height), and land portion dimensions. These parameter changes are designed to maximize cutting efficiency and ROP while keeping the manufacturing process within acceptable complexity boundaries

Inventive Principle:
Principle #35Parameter changes

3Reliability

If the PCD layer thickness is uniform, then manufacturing is easier, but cutting efficiency and durability are reduced

Engineering Contradiction:
Improvecutting efficiencyVSAvoidPCD layer fabrication
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The PCD layer thickness is varied across different zones of the cutting element: thicker on the land portion for structural support and durability, optimized thickness on the ramp portion for cutting efficiency, and appropriate thickness on the cutting face ridge for sustained performance. This local quality variation enhances both durability and cutting efficiency while maintaining manufacturability through zone-based fabrication control

Inventive Principle:
Principle #3Local quality

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 design enhances the drill bit's durability and ROP, reducing the need for frequent bit changes and lowering drilling costs by improving cutting efficiency and manufacturing simplicity.

Implementation Method 1

The ridge may be configured to split extrudate formed during drilling, thereby reducing the mechanical specific energy that must be expended to move the extrudate across the cutting face

Methodology Applied
Scientific EffectForce concentration: Mechanical Force

Implementation Method 2

a surrounding surface that is continuously curved along a curved path that extends at least partially about the curved second ridge end

Methodology Applied
Scientific EffectFluid flow direction: Fluid Spray

Data Source

PatentEP3784866B1Extrudate-producing ridged cutting element
Publication Date: 2022.11.09 NAT OILWELL VARCO LP
  • EP3784866B1 patent drawingFigure 1
  • EP3784866B1 patent drawingFigure 2A
  • EP3784866B1 patent drawingFigure 2B

AI summary

A cutting element (101) for a drill bit (112) includes a PCD cutting face (328) having a ridge (332) that extends away from the periphery towards the center of the cutting face, terminating in a curved, central most ridge end (339). The cutting face further includes a surrounding surface (336) consisting of the entire cutting face except for the ridge. The surrounding surface is free of flats and includes two side regions (330a, 330b) and a ramp region (334) therebetween. The surrounding surface (336) is continuously curved along a curved path that extends from the first side region to the ramp region to the other side region. In profile views, the surrounding surface may be linear moving from the top surface of the ridge to the periphery at every location along the curved path.