Downhole One-Way Coupling for High-Frequency Torsional Oscillations
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Solution Overview
Problem
High frequency torsional oscillations in downhole assemblies during drilling for geothermal energy or oil and gas drilling can cause significant damage to components like rotary steerable tools and PDC drill bits, and existing mitigation methods are inadequate due to the complexity of the drilling environment and the unpredictability of resonance frequencies.
Innovation Solution
A high frequency torsional oscillation mitigation tool with a one-way coupling mechanism that transmits torque in one direction while preventing it in the opposite direction, located between the drill string and the drill bit, to disrupt the transfer of kinetic energy and prevent resonance buildup.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a one-way coupling mechanism is introduced to mitigate high frequency torsional oscillations, then the reliability of the downhole assembly is improved, but the device complexity increases
Solution Approach 1:
A one-way coupling mechanism is introduced as an intermediary element between the drill string and drill bit. This coupling includes a driver connected to the drill string and a follower connected to the drill bit, with one-way elements that allow torque transmission in one direction while blocking it in the opposite direction. This intermediary device mitigates high frequency torsional oscillations by preventing the reflection of torque waves, thereby improving reliability without requiring complex active control systems or sensors.
2Reliability
If multiple sets of driving elements are distributed along the longitudinal axis, then the effectiveness of torque transmission is improved, but the manufacturing complexity increases
Solution Approach 1:
The one-way coupling mechanism is divided into multiple discrete driving elements distributed along the longitudinal axis of the mitigation tool. Each driving element includes its own one-way elements (such as sprags or overrunning clutches) positioned at different locations. This segmentation allows torque to be transmitted effectively through multiple points, improving reliability while enabling modular manufacturing and assembly of the tool components.
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 tool effectively reduces the likelihood of damage from high frequency torsional oscillations by altering the resonant system's boundary conditions, protecting sensitive components such as rotary steerable tools and drill bits from excessive strain and failure.
Implementation Method 1
a one-way coupling between the first end and the second end, the one-way coupling having a first part and a second part, the first part being connected to rotate with the first connector and the second part being connected to rotate with the second connector, the one-way coupling having an engaged condition in which the first part and the second part can rotate together in a first rotational direction and a disengaged condition in which the first part can rotate relative to the second part in a second rotational direction
Data Source
AI summary
A high frequency torsional oscillation mitigation tool for use in a downhole drilling assembly. The tool has a first end, a second end, and a one-way coupling therebetween. The one-way coupling has a first part connected to rotate with the first end and a second part connected to rotate with the second end. The one-way coupling has an engaged condition in which the first part and the second part can rotate together in a first rotational direction whereby drill string rotation can be communicated to the drill bit. The one-way coupling has a disengaged condition in which the first part can rotate relative to the second part in a second rotational direction. The one-way coupling can have multiple sets of driving elements along its longitudinal axis. The tool can include a locking mechanism to override the one-way coupling for recovering a stuck downhole assembly.