Up-drill Features on Fixed Cutter Drill Bits
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Solution Overview
Problem
Conventional drill bits experience significant wear on the top transition surfaces and transition edges during up-drilling and back reaming, leading to rounding of gage regions and accelerated wear, which compromises the drill bit's ability to maintain the desired borehole diameter.
Innovation Solution
The implementation of up-drill features on the top transition surfaces of the drill bit, which are passive during down-drilling and active during up-drilling or back reaming, utilizing hardfacing materials or carbide components to provide wear protection and cutting capabilities, strategically positioned between the gage regions and the shank.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional drill bits are used during up-drilling operations, then the drill bit can perform the up-drilling function, but significant wear occurs on the top transition surfaces and transition edges, leading to rounding of gage regions
Solution Approach 1:
The drill bit is divided into functional zones with distinct features: active cutting elements on blades for down-drilling, and passive up-drill features on top transition surfaces for up-drilling. This segmentation allows each region to be optimized for its specific function, with up-drill features providing wear protection during up-drilling operations while active cutting elements handle formation cutting during down-drilling.
Solution Approach 2:
Different regions of the drill bit are given different properties: the top transition surfaces are equipped with hardfacing materials or carbide components specifically where wear occurs during up-drilling, while the blade regions maintain their cutting capabilities. This localized enhancement of material properties at critical wear zones protects the gage region integrity without compromising overall drill bit functionality.
2Reliability
If hardfacing materials or carbide components are added to protect transition surfaces, then wear resistance improves, but device complexity increases
Solution Approach 1:
Hardfacing materials or carbide components are applied only to specific top transition surfaces where wear occurs during up-drilling operations, rather than covering the entire drill bit. This localized application of enhanced materials provides necessary wear resistance at critical zones while minimizing the overall complexity and material usage of the drill bit structure.
Solution Approach 2:
The up-drill features with hardfacing materials or carbide components are pre-installed on the top transition surfaces before the drill bit enters service. This preliminary preparation ensures that wear protection is already in place before up-drilling operations begin, preventing wear damage rather than requiring later repairs or modifications, thereby simplifying the overall operational complexity.
Data Source
AI summary
Earth-boring tools include at least one up-drill feature disposed on a transition surface so as to be passive during down drilling and active during up drilling and/or back reaming operations. Systems for down drilling and up drilling with drill bits comprising one or more up-drill features are also disclosed. Furthermore, methods for forming a borehole with an earth-boring tool including such up-drill features and for forming an earth-boring tool comprising such up-drill features are also disclosed.