Drill Bit Substrate Contact Prevention via Depth of Cut Control
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Solution Overview
Problem
Existing drilling technologies face challenges in preventing the substrate of cutting elements from contacting the formation during drilling, leading to excess friction, loss of cutters, and unstable bit runs, as the substrates are not effectively controlled to avoid contact with the geological formations.
Innovation Solution
A method is disclosed to calculate the substrate-based critical depth of cut to prevent the substrate of cutting elements from contacting the formation, involving modifications to drill bit design parameters such as cutter density, DOCC density, and rake angles to ensure the substrate does not contact the formation, and the use of depth of cut controllers to control the depth of cut effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the cutting element is designed to cut into the formation, then the cutting edge can effectively engage the formation to form wellbore, but the substrate may contact the formation causing excess friction and cutter loss
Solution Approach 1:
The patent applies preliminary action by pre-calculating the substrate-based critical depth of cut before drilling operations begin. The system determines the maximum depth at which the substrate will contact the formation and uses this information to configure depth of cut controllers that prevent substrate contact throughout the drilling process, thereby maintaining cutter stability while preserving drilling efficiency
Solution Approach 2:
The patent employs parameter changes by modifying drill bit design parameters including cutter density, DOCC density, and rake angles based on the calculated critical depth of cut. These parameter adjustments are made to ensure the substrate does not contact the formation, resolving the contradiction between effective cutting and substrate stability
2Productivity
If the depth of cut is increased to improve drilling speed, then productivity increases, but the substrate may contact the formation causing friction and instability
Solution Approach 1:
The patent implements feedback by using the calculated substrate-based critical depth of cut as a control parameter. Depth of cut controllers are configured with this critical value and continuously adjust the actual depth of cut during drilling to prevent substrate contact, thereby eliminating friction while maintaining optimal drilling speed through dynamic control
3Reliability
If the cutting element geometry is modified to prevent substrate contact, then substrate stability improves, but the cutting effectiveness may be reduced
Solution Approach 1:
The patent applies dynamics by making the depth of cut a dynamic parameter that adjusts during drilling operations. Rather than using fixed geometry that might compromise cutting effectiveness, the system dynamically controls the depth of cut based on the calculated critical value, ensuring substrate stability is maintained while preserving optimal cutting performance through real-time adjustments
Data Source
AI summary
In accordance with some embodiments of the present disclosure, a method of designing a drill bit comprises determining placements on a drill bit for a plurality of cutting elements at a plurality of radial coordinates of the drill bit. The method further comprises determining a substrate-based critical depth of cut for a substrate of each cutting element and generating a substrate-based critical depth of cut control curve based on the substrate-based critical depth of cut at each radial coordinate. The method also comprises comparing the substrate-based critical depth of cut control curve and the threshold critical depth of cut control curve and adjusting a drill bit design parameter if the substrate-based critical depth of cut control curve is less than or equal to the threshold critical depth of cut control curve at a radial coordinate.