Drill Bit DOCC Features for Stick-Slip Vibration Control
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Solution Overview
Problem
Earth-boring tools experience stick-slip vibrations due to fluctuations in weight on bit and transitions between subterranean formations, leading to increased torque and bit damage, with existing mitigation theories lacking validation from controlled down-hole measurements.
Innovation Solution
The implementation of depth of cut control (DOCC) features on earth-boring tools, which include first and second DOCC features with different surface areas and engagement rates to manage load distribution and control the depth of cut, thereby reducing stick-slip vibrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If higher weight on bit and lower rotary speed are used to enhance drilling performance, then drilling efficiency is improved, but stick-slip vibrations increase causing bit damage
Solution Approach 1:
The patent changes the physical parameters of the DOCC features (surface area, shape, location) to control the rate of engagement with the formation. By varying these parameters, the system can adjust load distribution characteristics to mitigate stick-slip vibrations while maintaining high weight on bit operations, thus resolving the contradiction between drilling efficiency and bit damage
Solution Approach 2:
The DOCC features act as intermediary elements between the cutting elements and the formation. These features with different surface areas serve as mediators that distribute load and control depth of cut, reducing the direct impact on cutting elements and thereby reducing bit damage while maintaining productivity
2Reliability
If multiple DOCC features with different surface areas are used to control load distribution, then stick-slip vibrations are reduced, but device complexity increases
Solution Approach 1:
The patent divides the load distribution function into multiple segments by providing several DOCC features with different surface areas. Each DOCC feature segment handles specific portions of the load, allowing fine-tuned control over engagement rates and load distribution, which mitigates stick-slip vibrations through distributed loading
Solution Approach 2:
The patent applies local quality by making each DOCC feature have specific surface area characteristics tailored to its location and function. Different regions of the bit have DOCC features with locally optimized surface areas to control engagement rates appropriately for each location, achieving vibration mitigation through localized load management
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 DOCC features effectively manage load distribution and control the depth of cut, reducing stick-slip vibrations and bit damage, enhancing drilling efficiency and reducing non-productive time by selectively engaging the subterranean formation at varying rates.
Implementation Method 1
The first DOCC feature comprises a first rubbing surface having a first surface area for contacting a subterranean formation and distributing a load attributable to applied weight on bit at a first rate of engagement
Data Source
AI summary
An earth-boring tool comprises a bit body and first and second depth of cut control (“DOCC”) features mounted thereon. The first and second DOCC features comprise a first rubbing surface having a first surface area and a second rubbing surface having a second surface area, respectively, for contacting a subterranean formation. The second surface area is different from the first surface area such that the first and second DOCC features distribute a load attributable to applied weight on bit over the first and second rubbing surfaces at different rates. Methods of forming an earth-boring tool include selecting first and second DOCC features having different rates of engagement with the subterranean formation and mounting the first and second DOCC features on a bit body.