Rolling DOCC Element Activation for Drill Bit Wear Control
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Solution Overview
Problem
Drill bits with fixed cutters face premature wear and damage due to friction and forces during drilling, leading to inefficient depth control and bit damage, especially in complex wellbore formations.
Innovation Solution
The implementation of moveable depth of cut control (DOCC) assemblies with rolling elements that change exposure positions during drilling, allowing for one-time activation or deactivation to adjust bit aggressiveness, using retention members like burst discs, shelves, shear pins, or shape memory materials to transition from a first to a second exposure position, thereby controlling the depth of cut.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If fixed cutter drill bits are used with downward force and rotation to cut formation, then drilling function is achieved, but friction and forces cause premature wear and damage to cutting elements
Solution Approach 1:
The patent applies dynamics by making the DOCC element movable rather than fixed. The rolling DOCC element can move between exposed and retracted positions based on drilling conditions, allowing the system to adapt to varying formation resistances and optimize both cutting efficiency and element protection dynamically during drilling operations.
Solution Approach 2:
The patent changes the parameter of DOCC element exposure position from fixed to variable. By controlling the exposure position of the rolling DOCC element (fully exposed, partially exposed, or retracted), the system can adjust depth of cut control intensity to match different drilling phases and formation conditions, thereby reducing premature wear while maintaining productivity.
2Reliability
If DOCC elements are secured to bit body to limit depth of cut, then cutting element protection is improved, but bit aggressiveness cannot be adjusted for different drilling phases
Solution Approach 1:
The rolling DOCC element provides dynamic adaptability by being able to move between different exposure positions. This allows the bit to transition from protective mode (DOCC exposed) during initial drilling to aggressive cutting mode (DOCC retracted) during later stages, or vice versa based on formation conditions, thus achieving both protection and adjusted aggressiveness as needed.
Solution Approach 2:
The patent segments the DOCC function into multiple exposure states (exposed, partially exposed, retracted) rather than a single fixed position. This segmentation allows different portions of the drilling operation to have different depth control characteristics, enabling the system to provide both protection during sensitive phases and aggressiveness during productive phases.
3Manufacturing precision
If rolling DOCC element is retained at first exposure position, then initial depth control is achieved, but element cannot respond to changing downhole conditions
Solution Approach 1:
The rolling DOCC element transitions from a static retained position to a dynamic movable position that can respond to downhole conditions. The element can be biased by various mechanisms (weight, pressure, temperature-responsive materials) to automatically adjust its exposure position based on real-time downhole environment, providing both initial precision and ongoing adaptability.
Solution Approach 2:
The system incorporates feedback mechanisms where downhole conditions (pressure, temperature, formation resistance) automatically influence the DOCC element position through responsive retention members or biasing mechanisms. This feedback loop allows the DOCC element to sense and respond to changing conditions without external intervention, maintaining both initial control accuracy and adaptive response.
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
This solution enhances drilling efficiency by allowing for controlled bit aggressiveness changes, reducing wear, and minimizing stick-slip, while maintaining reliability and cost-effectiveness by enabling specific engagement profiles for different drilling phases.
Implementation Method 1
the retention member comprises a shape memory material configured to release the rolling element downhole by changing shape in response to reaching a threshold temperature
Implementation Method 2
the retention member comprises a burst disc configured to release the rolling element downhole by bursting in response to reaching a threshold pressure
Implementation Method 3
the retention member comprises a shear pin configured to release the rolling element downhole by shearing in response to reaching a threshold force
Implementation Method 4
contact between the cutting elements and downhole formations generates friction and other forces
Data Source
AI summary
A depth of cut control (DOCC) assembly includes a DOCC element positioned in a retainer pocket along a drill bit blade to limit a depth of cut of one or more fixed cutters. A retention member initially retains the DOCC element within the retainer pocket at a first exposure position. The retention member is configured to release the DOCC element downhole to allow one-way movement of the DOCC element to a second exposure position.