Hybrid Drill Bit Combining Rolling and Fixed Blades
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Solution Overview
Problem
Existing earth-boring bits face challenges in achieving a balance between cutting aggressiveness and durability, as rolling-cutter bits are less aggressive but more durable, while fixed-blade cutter bits are more aggressive but prone to torque limitations and vibrations, leading to inefficiencies in drilling various formations.
Innovation Solution
A hybrid earth-boring bit design incorporating both rolling and fixed-blade cutters, with adjustable cutting aggressiveness achieved by varying the angular relationship, effective projection, and arrangement of cutting elements to optimize the balance between rate-of-penetration and durability, allowing for tailored performance based on drilling conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If fixed-blade cutter bits are used to increase cutting aggressiveness and rate-of-penetration, then drilling speed is improved, but torque limitations and vibrations worsen
Solution Approach 1:
The patent combines fixed-blade cutters and rolling cutters on the same bit body to create a hybrid bit that integrates the high cutting aggressiveness of fixed blades with the torque stability and durability of rolling cutters, resolving the contradiction between productivity and reliability
Solution Approach 2:
The patent applies different cutter types at different locations on the bit body, with fixed-blade cutters positioned to provide aggressive cutting where needed and rolling cutters positioned to provide stability and handle abrasive formations, allowing localized optimization of cutting performance and torque characteristics
2Reliability
If rolling-cutter bits are used to increase durability and reduce torque issues, then reliability is improved, but cutting aggressiveness and drilling speed worsen
Solution Approach 1:
The hybrid bit merges rolling cutters for durability with fixed-blade cutters for cutting aggressiveness, allowing the bit to maintain reliability while improving productivity through the complementary actions of both cutter types
Solution Approach 2:
The fixed-blade cutters perform preliminary aggressive cutting to break up formation material, which then allows the rolling cutters to efficiently remove the broken material, dividing the cutting task to optimize both aggressiveness and durability
3Adaptability or versatility
If hybrid bits with both rolling and fixed-blade cutters are used to balance cutting aggressiveness and durability, then versatility is improved, but device complexity worsens
Solution Approach 1:
The bit body is segmented into different zones with specific cutter types arranged in patterns that can be optimized for different formation types, allowing versatility while maintaining a systematic and manageable complexity through modular zoning
Data Source
AI summary
A hybrid earth-boring bit comprising a bit body having a central axis, at least one, preferably three fixed blades, depending downwardly from the bit body, each fixed blade having a leading edge, and at least one rolling cutter, preferably three rolling cutters, mounted for rotation on the bit body. A rolling cutter is located between two fixed blades.