Nonplanar Cutting Element Geometry for Drilling Tool Durability
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Solution Overview
Problem
Downhole drilling tools with super hard material layers face stress and wear issues due to intense forces, torques, and temperature variations, leading to spalling, delamination, or fracture of the cutting elements, which reduces their efficacy and drill bit wear life.
Innovation Solution
The use of directional cutting elements with a cutting face featuring an elongated protrusion having a concave surface and specific geometrical features such as a border, face chamfer, and sloped surfaces, which provide a front rake angle and edge chamfer, optimizing cutting forces and distributing stress uniformly to enhance durability and cutting efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If cutting elements are made with super hard material layers to penetrate hard and abrasive formations, then cutting capability is improved, but stress concentration leads to spalling, delamination, or fracture reducing durability
Solution Approach 1:
The cutting element incorporates a nonplanar face with varying geometries (protrusions, recesses, angled surfaces) at specific locations to create localized stress distribution patterns. This allows different regions of the cutting element to have optimized properties for both cutting performance and stress resistance, rather than using a uniform geometry throughout.
Solution Approach 2:
The cutting element features an asymmetric nonplanar face with protrusions and recesses that break the symmetry of traditional flat cutting surfaces. This asymmetric geometry creates more uniform stress distribution during cutting operations, reducing stress concentration points that would otherwise lead to spalling and delamination while maintaining effective cutting edges.
2Productivity
If cutting elements are subjected to intense forces and torques during drilling operations, then formation penetration is achieved, but stress concentration reduces cutting element efficacy and drill bit wear life
Solution Approach 1:
The invention changes the geometric parameters of the cutting element face from a flat surface to a nonplanar surface with specific features (protrusions, recesses, angles). These parameter changes optimize the distribution of mechanical stresses during cutting, allowing the element to withstand intense forces and torques while maintaining cutting efficacy and extending drill bit wear life.
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 directional cutting elements improve cutting efficiency and durability by reducing shear forces and torque, while the optimized geometry mitigates stress concentration, leading to increased tool life and formation removal rates.
Implementation Method 1
The substrates and adjacent diamond grain layers are then compressed under HPHT conditions which promotes a sintering of the diamond grains to form a polycrystalline diamond structure.
Implementation Method 2
Such cutting elements may be made with a super hard material layer to penetrate hard and abrasive earthen formations... PCD cutters typically comprise diamond material formed on a supporting substrate (typically a cemented tungsten carbide (WC) substrate) and bonded to the substrate under high temperature, high pressure (HTHP) conditions.
Implementation Method 3
The cutters 18 may deform the earth formation by scraping, crushing, and shearing.
Implementation Method 4
The cutters 18 may deform the earth formation by scraping, crushing, and shearing.
Data Source
AI summary
A drilling tool having a body, at least one blade extending from the body, and a first cutting element attached to the at least one blade. The first cutting element includes a cutting face at an opposite axial end from a base, a side surface extending from the base to the cutting face, an edge formed at the intersection between the cutting face and the side surface, and an elongated protrusion formed at the cutting face and extending between opposite sides of the edge. The elongated protrusion has a geometry including a border extending around a concave surface, a face chamfer formed around the border, and sloped surfaces extending between the border and the edge. An edge chamfer is between the face chamfer and the edge.