Hybrid Drill Bit with Segmented PDC and Conical Cutters
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Solution Overview
Problem
Conventional PDC drill bits face challenges in maintaining stability and durability while drilling through hard formations, often requiring increased weight-on-bit, which leads to premature wear and increased drilling costs due to the need for frequent bit changes and additional stress on the drill string.
Innovation Solution
The use of hybrid cutting structures incorporating both planar and conical cutting elements on a drill bit, where conical cutting elements provide additional cutting action modes, such as compressive fracture, and are strategically positioned to optimize drilling performance across varying formation hardnesses, reducing the need for excessive weight-on-bit and enhancing bit life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If conventional PDC drill bits are used to drill through hard formations, then drilling can proceed, but the bit requires increased weight-on-bit which leads to premature wear and increased drilling costs
Solution Approach 1:
The drill bit is segmented into different cutting element types (PDC cutters and conical cutting elements) positioned at different radial locations. The PDC cutters are located at an outer radial position while conical cutting elements are located at an inner radial position, allowing each type to perform optimally in its designated zone and reducing the need for excessive weight-on-bit.
Solution Approach 2:
Different cutting elements are applied to different radial positions based on local formation engagement requirements. The conical cutting elements at inner radial positions provide compressive fracture action for hard formations, while PDC cutters at outer radial positions provide shearing action, optimizing cutting performance locally across the bit face.
2Productivity
If increased weight-on-bit is applied to drill through hard formations, then penetration can be achieved, but the drill string experiences additional stress and bit wear increases
Solution Approach 1:
The cutting structure is segmented into multiple rows with different cutting element types. The hybrid arrangement allows the bit to maintain high rate of penetration through hard formations using conical cutting elements at inner radial positions while PDC cutters at outer radial positions reduce overall bit wear by distributing the cutting load.
Solution Approach 2:
The drill bit employs a composite cutting structure combining PDC cutters and conical cutting elements made of different materials and geometries. This composite approach enables the bit to drill through varied formation hardnesses effectively while minimizing wear through the complementary actions of the two cutting element types.
3Adaptability or versatility
If conventional cutting elements are used, then the bit structure is simple, but the bit cannot maintain stability and durability across varying formation hardnesses
Solution Approach 1:
The cutting structure is divided into multiple functional zones with different cutting element types arranged in specific radial positions. This segmentation allows the bit to adapt to varying formation hardnesses by engaging appropriate cutting elements for each formation type, achieving versatility while maintaining a relatively simple overall bit structure.
Solution Approach 2:
The hybrid cutting structure provides multi-functionality by combining PDC cutters and conical cutting elements that can handle different formation conditions. This universal design allows a single bit to effectively drill through soft, medium, and hard formations without requiring multiple specialized bits, balancing adaptability with structural complexity.
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 approach allows for effective drilling in soft, medium, and hard formations with improved rate of penetration and extended bit life, reducing drilling costs by minimizing bit wear and stabilizing the drill bit, thus enabling longer drilling sessions without frequent trips and reduced stress on the drill string.
Implementation Method 1
conical cutting elements provide additional cutting action modes, such as compressive fracture
Implementation Method 2
the rotating bit engages the earthen formation causing the bit to cut through the formation material by either abrasion, fracturing, or shearing action
Implementation Method 3
each cutting element comprises an elongate and generally cylindrical tungsten carbide substrate that is received and secured in a pocket formed in the surface of one of the blades. The cutting elements typically includes a hard cutting layer of polycrystalline diamond (PCD) or other superabrasive materials
Data Source
AI summary
A drill bit for drilling a borehole in earth formations may include a bit body having a bit axis and a bit face; a plurality of blades extending radially along the bit face; and a plurality of cutting elements disposed on the plurality of blades, the plurality of cutting elements comprising: at least one cutter comprising a substrate and a diamond table having a substantially planar cutting face; and at least two non-planar cutting elements comprising a substrate and a diamond layer having a non-planar cutting end, wherein in a rotated view of the plurality of cutting elements into a single plane, the at least one cutter is located a radial position from the bit axis that is intermediate the radial positions of the at least two non-planar cutting elements.