Downhole Cutting Element with Positive Rake Angle and Non-Planar Interface
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Cutting elements in drill bits, particularly those with superhard material layers bonded to carbide substrates, often experience stress-related failures such as spalling and delamination due to intense forces and temperature differentials during drilling, leading to reduced wear-life and efficiency.
Innovation Solution
A downhole fixed bladed bit design featuring cutting elements with a non-planar interface and a conical geometry, where the superhard material is bonded to a cemented metal carbide substrate at a positive rake angle, inducing fractures ahead of the cutting element and utilizing a sintered polycrystalline diamond with less than 5% catalyst metal concentration, which is more resistant to wear and stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If cutting elements use superhard material layers bonded to carbide substrates, then wear resistance is improved, but stress-related failures such as spalling and delamination occur due to intense forces and temperature differentials
Solution Approach 1:
The patent changes the bonding interface geometry from planar to non-planar (concave or convex), and positions the cutting element at a positive rake angle. These parameter changes modify the stress distribution at the interface, reducing tensile stresses that cause delamination and spalling while maintaining wear resistance of the superhard material layer.
Solution Approach 2:
The patent uses a composite structure consisting of a superhard material layer (such as polycrystalline diamond or cubic boron nitride) bonded to a carbide substrate. This composite design combines the wear resistance of superhard materials with the toughness of carbide, while the optimized interface geometry ensures reliable bonding under drilling conditions.
2Use of energy by moving object
If cutting elements are positioned at a positive rake angle, then energy required to remove rock is reduced, but the bonding interface geometry becomes more complex
Solution Approach 1:
The patent introduces a positive rake angle parameter for the cutting element positioning and a non-planar interface geometry parameter. These parameter changes optimize the cutting action to reduce energy consumption by inducing favorable fracture patterns in the rock, while the complexity of the bonding interface is managed through precise manufacturing of the concave or convex geometry.
3Strength
If sintered polycrystalline diamond with less than 5% catalyst metal concentration is used, then wear resistance is improved, but manufacturing complexity increases
Solution Approach 1:
The patent specifies a parameter change in the catalyst metal concentration to less than 5%, which optimizes the sintering process and produces a superhard material layer with enhanced wear resistance. This parameter control during manufacturing ensures reliable bonding and reduced porosity, though it requires precise control during the sintering process.
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 durability and efficiency of the cutting elements by reducing the energy required to remove rock formations, prolonging the drill bit's life and improving drilling performance by inducing fractures peripherally and compressively, thus reducing the specific energy needed for rock removal.
Implementation Method 1
The substrates and adjacent diamond crystal layers are then compressed under HPHT conditions which promotes a sintering of the diamond grains to form the polycrystalline diamond structure.
Implementation Method 2
inducing fractures ahead of the cutting element and utilizing a sintered polycrystalline diamond with less than 5% catalyst metal concentration, which is more resistant to wear and stress... inducing fractures peripherally and compressively, thus reducing the specific energy needed for rock removal
Data Source
AI summary
A downhole fixed bladed bit comprises a working surface comprising a plurality of blades converging at a center of the working surface and diverging towards a gauge of the bit, at least on blade comprising a cutting element comprising a superhard material bonded to a cemented metal carbide substrate at a non-planer interface, the cutting element being positioned at a positive rake angle, and the superhard material comprising a substantially conical geometry with an apex comprising a curvature.