Drag Member for Simultaneous Drilling and Reaming
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Solution Overview
Problem
During simultaneous drilling and reaming in well bores, the sudden shift in weight and torque from the drill bit to the reamer can cause temporary dysfunction, leading to increased torque, stick slip, whirl, and vibration, resulting in loss of smoothness and circularity in the reamed borehole due to the reamer's inability to handle softer and more brittle formation layers effectively.
Innovation Solution
Incorporating a drag member in the bottom hole assembly that extends drag elements to contact the well bore wall, reducing the weight and torque on the reamer's cutters by creating a drag force, which is activated when excessive force is sensed, thereby stabilizing the drilling and reaming process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If simultaneous drilling and reaming is performed without drag control, then faster penetration rates and reduced rig time are achieved, but the reamer experiences excessive weight and torque causing dysfunction, stick slip, whirl, and vibration
Solution Approach 1:
The drag member acts as an intermediary element between the reamer and the wellbore wall. It introduces a controlled drag force that opposes the excessive weight and torque on the reamer cutters, preventing dysfunction and vibrations while allowing simultaneous drilling and reaming to proceed at high penetration rates
Solution Approach 2:
The drag member provides a counteracting drag force that balances the excessive weight and torque forces acting on the reamer. By contacting the wellbore wall, it creates an opposing force that prevents the reamer from experiencing excessive loads that would cause stick slip, whirl, and vibration
2Productivity
If the reamer handles softer and more brittle formation layers alone, then drilling progresses, but the reamer experiences sudden shifts in weight and torque causing loss of smoothness and circularity
Solution Approach 1:
The drag member serves as a mediator that stabilizes the reaming process in softer and more brittle formation layers. By providing controlled drag force, it prevents sudden weight and torque shifts that would otherwise cause the reamer to lose smoothness and circularity control
Solution Approach 2:
The drag member provides continuous feedback through drag force that responds to formation characteristics. As the reamer encounters varying formation conditions, the drag member automatically adjusts the force distribution, maintaining stable cutting conditions and preserving borehole smoothness and circularity
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 drag member effectively reduces the weight and torque on the reamer's cutters, preventing dysfunction and maintaining smoothness and circularity of the borehole by damping vibrations and frictionally opposing excessive forces, thus enhancing the drilling and reaming efficiency.
Implementation Method 1
extending drag elements from the bottom hole assembly to contact a wall of the well bore and reduce the force on the cutters of the reamer
Implementation Method 2
maintaining smoothness and circularity of the borehole by damping vibrations and frictionally opposing excessive forces
Data Source
AI summary
Drilling dysfunction during simultaneous down-hole drilling and reaming is reduced by obtaining an indication of force on cutters of a reamer, determining whether or not the indication indicates an excessive force, and upon determining that the indication indicates an excessive force, extending drag elements from the bottom hole assembly to contact a wall of the well bore and reduce the force on the cutters of the reamer. The indication of force on the cutters can be obtained by sensing the weight on the drill bit, and the determination can be done by comparing the indicated weight on the drill bit to a first threshold and a second threshold.