Pointed Diamond Working Ends on Shear Bits
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Cutting elements in rotary drag bits face stress-related issues such as delamination and fracture due to intense forces and temperature differentials, leading to reduced wear life and efficiency during drilling operations.
Innovation Solution
The use of a carbide substrate with a diamond working end having a pointed geometry and a positive rake angle between 25 and 85 degrees, bonded using a high-pressure high-temperature press apparatus, which enhances the cutting performance and reduces wear by producing larger, more efficient chips.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a conventional carbide substrate with superhard material layer is used, then the cutting element can withstand intense forces and torques, but the superhard material layer delaminates or fractures due to stress, reducing wear life
Solution Approach 1:
The cutting element uses a composite structure combining a carbide substrate with a sintered superhard material layer (such as polycrystalline diamond or cubic boron nitride) bonded through HPHT conditions. This composite construction allows the substrate to provide structural strength while the superhard layer provides wear resistance, resolving the contradiction between withstanding intense forces and preventing delamination.
Solution Approach 2:
The invention employs high pressure and high temperature (HPHT) parameters during the bonding process to transform the interface between substrate and superhard layer. By changing the physical parameters (pressure and temperature) during bonding, the interface strength is enhanced, preventing delamination and fracture under operational stresses.
2Productivity
If the cutting element operates under high stress conditions, then drilling penetration is achieved, but stress-related failures occur reducing efficiency
Solution Approach 1:
The cutting element is pre-conditioned through HPHT bonding to create a stress-resistant interface before actual drilling operations begin. This preliminary high-pressure high-temperature treatment prepares the cutting element to withstand the intense forces and torques that will be encountered during drilling, preventing stress-related failures and extending operational life while maintaining penetration efficiency.
3Ease of manufacture
If traditional cutting geometries are used, then manufacturing is straightforward, but wear life is reduced due to increased abrasive surface area
Solution Approach 1:
The invention uses HPHT parameters to sinter diamond or cubic boron nitride grains into a dense, low-surface-area working end. By changing the physical state and density of the superhard material through controlled pressure and temperature, the abrasive surface area is minimized while maintaining ease of manufacture through established HPHT processing techniques.
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 configuration results in minimal wear and improved drilling efficiency, producing 40 to 60 percent of cuttings with a volume of 0.5 to 10 cubic centimeters, and extends the life of the cutting elements by reducing abrasive surface area and energy consumption.
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
The substrates and adjacent diamond crystal layers are then compressed under HPHT conditions which promotes a sintering of the diamond grains
Data Source
AI summary
In one aspect of the present invention, a drill string has a drill bit with a body intermediate a shank and a working face. The working face has a plurality of blades converging at a center of the working surface and diverging towards a gauge of the working face. At least one blade has a cutting element with a carbide substrate bonded to a diamond working end with a pointed geometry. The diamond working end also has a central axis which intersects an apex of the pointed geometry. The axis is oriented between a 25 and 85 degree positive rake angle.