Fixed-Cutter Drill Bits with Stepped Secondary Cutting Edges
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Solution Overview
Problem
Existing fixed cutter drill bits face challenges in cutting efficiency and durability, leading to increased drilling time and costs due to frequent bit changes, which are influenced by the cutting efficiency of cutter elements and the exposed surface area of diamond during drilling.
Innovation Solution
The design of cutter elements with a stepped cutting face featuring a primary and secondary cutting surface, oriented to engage the formation at different times, enhances cutting efficiency and durability by increasing the effective cutting area and reducing wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a conventional single cutting surface design is used, then the device complexity is low, but the cutting efficiency and durability are insufficient
Solution Approach 1:
The cutting face is segmented into multiple discrete cutting surfaces (primary, secondary, and tertiary cutting surfaces) that are axially spaced apart. Each surface provides additional cutting edges that engage the formation at different depths, effectively increasing the cutting efficiency without requiring a complete redesign of the cutter element structure.
Solution Approach 2:
The invention transitions from a single-planar cutting surface to a multi-level stepped geometry by adding axial dimensionality. The cutting surfaces are arranged at different axial positions, creating a stepped configuration that increases the effective cutting area and engagement with the formation while maintaining a manageable structural complexity.
2Productivity
If the exposed surface area of diamond is increased, then the cutting efficiency improves, but the wear resistance decreases due to faster diamond consumption
Solution Approach 1:
The stepped cutting surfaces are designed to engage the formation in a sequential manner during drilling. The primary cutting surface engages first, followed by secondary and tertiary surfaces as the cutter element wears or as drilling depth increases. This preliminary arrangement of multiple cutting surfaces ensures continuous cutting efficiency while distributing wear across multiple surfaces, thereby extending drill bit lifespan.
3Productivity
If a single cutting edge is used, then the device complexity is low, but the cutting efficiency and rate of penetration are limited
Solution Approach 1:
The cutting face is divided into multiple segmented cutting surfaces (primary, secondary, tertiary) that are axially spaced. Each surface contributes to the overall rate of penetration by engaging the formation at different stages, effectively multiplying the cutting action without requiring an overly complex structure.
Solution Approach 2:
Each cutting surface on the stepped geometry serves multiple functions: initial cutting, continued penetration, and wear compensation. The multi-functional design allows a single cutter element to perform the work of multiple cutting edges, increasing the rate of penetration while maintaining reasonable device 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
The stepped cutting face design improves cutting efficiency and extends the drill bit's lifespan, reducing the frequency of bit changes and lowering drilling costs by optimizing the engagement and shearing action on subterranean formations.
Implementation Method 1
The drilling fluid exiting the face of the bit through nozzles or ports performs several functions. In particular, the fluid removes formation cuttings (for example, rock chips) from the cutting structure of the drill bit.
Implementation Method 2
Still further, the drilling fluid removes heat, caused by contact with the formation, from the cutter elements to prolong cutter element life.
Data Source
AI summary
A cutter element for a fixed cutter drill bit configured to drill a borehole in a subterranean formation includes a base having a central axis, a first end, a second end, and a radially outer cylindrical surface extending axially from the first end to the second end. In addition, the cutter element includes a cutting layer fixably mounted to the first end of the base. The cutting layer includes a stepped cutting face distal the base and a radially outer cylindrical surface extending axially from the cutting face to the radially outer cylindrical surface of the base. The radially outer cylindrical surface of the cutting layer is contiguous with the radially outer cylindrical surface of the base. The stepped cutting face includes a first step, a second step axially spaced from the first step, and a riser axially positioned between the first step and the second step. The first step is axially positioned between the riser and the base.