Rolling Depth of Cut Controller with Clamshell Retainer
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Solution Overview
Problem
Conventional fixed-cutter drill bits face issues with wear and efficiency due to stick-slip and whirl conditions, which can damage the drill bit and hinder drilling operations, as the PDC cutters wear down and fail over time.
Innovation Solution
The implementation of rolling depth of cut controllers (DOCCs) secured within slots on the drill bit, featuring a retainer assembly with a rotating element that engages the subterranean formation to reduce friction and maintain a steady depth of cut, thereby preventing stick-slip and whirl.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If PDC cutters continuously contact the formation to cut into the subterranean formation, then the drilling depth increases, but the PDC cutters wear down and fail over time
Solution Approach 1:
The patent introduces a rolling depth of cut controller with a rolling element that rotates during drilling operations. This dynamic component periodically enters and exits engagement with the formation, creating a rolling motion that controls depth of cut while reducing continuous contact wear on fixed cutters. The rolling element's rotation provides periodic renewal of the cutting interface, extending cutter life while maintaining productivity.
2Productivity
If fixed-cutter drill bit rotates to penetrate the subterranean formation, then the drilling efficiency improves, but stick-slip and whirl conditions occur causing damage to the drill bit
Solution Approach 1:
The rolling depth of cut controller introduces a dynamic rolling element that rotates during drilling, creating periodic motion that prevents the static friction and vibration conditions leading to stick-slip and whirl. The rolling motion continuously changes the contact point and engagement characteristics, disrupting the conditions that cause harmful vibrations and instability during drilling operations.
Solution Approach 2:
The rolling depth of cut controller acts as an intermediary component between the drill bit and the formation. This intermediate rolling element mediates the interaction by providing a controlled rolling contact that reduces direct friction and prevents the harmful stick-slip conditions between the fixed cutters and the formation, thereby protecting the drill bit from damage.
3Ease of operation
If rolling depth of cut controller is implemented with a rolling element, then friction is reduced and depth of cut is controlled, but the device complexity increases
Solution Approach 1:
The rolling depth of cut controller applies the rolling mechanism locally at the depth of cut control point rather than throughout the entire drill bit. This localized implementation provides friction reduction and depth control benefits while minimizing the overall complexity increase, as only a specific portion of the drill bit assembly incorporates the rolling element mechanism.
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 rolling DOCCs enhance drilling efficiency by reducing wear on fixed cutters, minimizing damage to the drill bit, and maintaining a consistent depth of cut, thus improving the overall drilling process.
Implementation Method 1
Rotation of the rolling element described herein may reduce friction at the interface between the drill bit and the formation
Data Source
AI summary
A rolling depth of cut controller (DOCC) includes a first retainer including a body portion having an arcuate inner surface. The body portion extends partially around a central axis between the inner surface and an outer surface from a mating surface to an engagement surface. Further, the body portion extends axially along the central axis. The rolling DOCC also includes a second retainer secured to the first retainer at the mating surface via at least one fastening feature. Additionally, the rolling DOCC includes a rolling element disposed at least partially within a cavity formed between the first retainer and the second retainer. The rolling element is configured to rotate within the cavity about the central axis, and an exposed portion of the rolling element is configured to provide depth-of-cut control for a drill bit.